diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/Instrument.kt b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
index b8ef1bc..92a896c 100644
--- a/app/src/main/java/com/lukas/music/instruments/Instrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
@@ -23,6 +23,7 @@
     abstract fun startNote(note: Note)
     abstract fun stop()
     abstract fun stopNote(note: Note)
+    abstract fun destroy()
 
     companion object {
         val instruments = mutableListOf<Instrument>()

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/Instrument.kt b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
index b8ef1bc..92a896c 100644
--- a/app/src/main/java/com/lukas/music/instruments/Instrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
@@ -23,6 +23,7 @@
     abstract fun startNote(note: Note)
     abstract fun stop()
     abstract fun stopNote(note: Note)
+    abstract fun destroy()
 
     companion object {
         val instruments = mutableListOf<Instrument>()
diff --git a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
index 0bb7281..b4c68a4 100644
--- a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
@@ -63,9 +63,14 @@
         endNote(id)
     }
 
+    fun destroy() {
+        destroy(id)
+    }
+
     private external fun createInstrument(): Int
     private external fun setInstrumentWaveform(id: Int, waveform: Int)
     private external fun startNote(id: Int, frequency: Double)
     private external fun endNote(id: Int)
     private external fun setVolume(id: Int, volume: Float)
+    private external fun destroy(id: Int)
 }
\ No newline at end of file

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/Instrument.kt b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
index b8ef1bc..92a896c 100644
--- a/app/src/main/java/com/lukas/music/instruments/Instrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
@@ -23,6 +23,7 @@
     abstract fun startNote(note: Note)
     abstract fun stop()
     abstract fun stopNote(note: Note)
+    abstract fun destroy()
 
     companion object {
         val instruments = mutableListOf<Instrument>()
diff --git a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
index 0bb7281..b4c68a4 100644
--- a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
@@ -63,9 +63,14 @@
         endNote(id)
     }
 
+    fun destroy() {
+        destroy(id)
+    }
+
     private external fun createInstrument(): Int
     private external fun setInstrumentWaveform(id: Int, waveform: Int)
     private external fun startNote(id: Int, frequency: Double)
     private external fun endNote(id: Int)
     private external fun setVolume(id: Int, volume: Float)
+    private external fun destroy(id: Int)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
index 8b1ba50..2b43524 100644
--- a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
@@ -49,4 +49,8 @@
             stop()
         }
     }
+
+    override fun destroy() {
+        internalInstrument.destroy()
+    }
 }
\ No newline at end of file

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/Instrument.kt b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
index b8ef1bc..92a896c 100644
--- a/app/src/main/java/com/lukas/music/instruments/Instrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
@@ -23,6 +23,7 @@
     abstract fun startNote(note: Note)
     abstract fun stop()
     abstract fun stopNote(note: Note)
+    abstract fun destroy()
 
     companion object {
         val instruments = mutableListOf<Instrument>()
diff --git a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
index 0bb7281..b4c68a4 100644
--- a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
@@ -63,9 +63,14 @@
         endNote(id)
     }
 
+    fun destroy() {
+        destroy(id)
+    }
+
     private external fun createInstrument(): Int
     private external fun setInstrumentWaveform(id: Int, waveform: Int)
     private external fun startNote(id: Int, frequency: Double)
     private external fun endNote(id: Int)
     private external fun setVolume(id: Int, volume: Float)
+    private external fun destroy(id: Int)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
index 8b1ba50..2b43524 100644
--- a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
@@ -49,4 +49,8 @@
             stop()
         }
     }
+
+    override fun destroy() {
+        internalInstrument.destroy()
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt b/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
index c6dae83..26e4fbb 100644
--- a/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
@@ -69,4 +69,10 @@
             }
         }
     }
+
+    override fun destroy() {
+        for (instrument in internalInstruments) {
+            instrument.destroy()
+        }
+    }
 }
\ No newline at end of file

diff --git a/app/src/main/cpp/AudioHost.cpp b/app/src/main/cpp/AudioHost.cpp
index dc80bd1..8e98b44 100644
--- a/app/src/main/cpp/AudioHost.cpp
+++ b/app/src/main/cpp/AudioHost.cpp
@@ -15,6 +15,9 @@
     }
     AudioHost *thiz = static_cast<AudioHost *>(userData);
     for (auto const &instrument: *thiz->instruments) {
+        if (!instrument) {
+            continue;
+        }
         instrument->render(buffer, sampleCount);
     }
     for (uint32_t i = 0; i < sampleCount; i++) {
diff --git a/app/src/main/cpp/JavaFunctions.cpp b/app/src/main/cpp/JavaFunctions.cpp
index 61b6e73..5505a35 100644
--- a/app/src/main/cpp/JavaFunctions.cpp
+++ b/app/src/main/cpp/JavaFunctions.cpp
@@ -8,7 +8,7 @@
 static AudioHost *audioHost;
 
 
-template <class _InputIterator>
+template<class _InputIterator>
 void *listGet(_InputIterator iterator, uint32_t n) {
     for (uint32_t i = 0; i < n; i++) {
         iterator++;
@@ -16,6 +16,18 @@
     return *iterator;
 }
 
+Instrument *getInstrument(uint32_t id) {
+    return static_cast<Instrument *>(listGet(audioHost->instruments->begin(), id));
+}
+
+template<class _InputIterator>
+void listSet(_InputIterator iterator, uint32_t n, void *value) {
+    for (uint32_t i = 0; i < n; i++) {
+        iterator++;
+    }
+    *iterator = static_cast<Instrument *>(value);
+}
+
 extern "C" {
 
 JNIEXPORT void JNICALL
@@ -34,17 +46,13 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_startNote(JNIEnv *env, jobject thiz,
                                                               jint id, jdouble frequency) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->startNote(frequency);
+    getInstrument(id)->startNote(frequency);
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_endNote(JNIEnv *env, jobject thiz,
                                                             jint id) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->endNote();
+    getInstrument(id)->endNote();
 }
 JNIEXPORT void JNICALL
 Java_com_lukas_music_ui_fragments_PlayFragment_setMasterVolume(JNIEnv *env, jobject thiz,
@@ -54,16 +62,18 @@
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setInstrumentWaveform(JNIEnv *env, jobject thiz,
                                                                           jint id, jint waveform) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->setWaveform(static_cast<WaveformType>(waveform));
+    getInstrument(id)->setWaveform(static_cast<WaveformType>(waveform));
 }
 
 JNIEXPORT void JNICALL
 Java_com_lukas_music_instruments_InternalInstrument_setVolume(JNIEnv *env, jobject thiz, jint id,
                                                               jfloat volume) {
-    Instrument *instrument = static_cast<Instrument *>(listGet(audioHost->instruments->begin(),
-                                                               id));
-    instrument->wave->amplitude = volume;
+    getInstrument(id)->wave->amplitude = volume;
+}
+
+JNIEXPORT void JNICALL
+Java_com_lukas_music_instruments_InternalInstrument_destroy(JNIEnv *env, jobject thiz, jint id) {
+    listSet(audioHost->instruments->begin(), id, nullptr);
+    delete getInstrument(id);
 }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/Instrument.kt b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
index b8ef1bc..92a896c 100644
--- a/app/src/main/java/com/lukas/music/instruments/Instrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/Instrument.kt
@@ -23,6 +23,7 @@
     abstract fun startNote(note: Note)
     abstract fun stop()
     abstract fun stopNote(note: Note)
+    abstract fun destroy()
 
     companion object {
         val instruments = mutableListOf<Instrument>()
diff --git a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
index 0bb7281..b4c68a4 100644
--- a/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/InternalInstrument.kt
@@ -63,9 +63,14 @@
         endNote(id)
     }
 
+    fun destroy() {
+        destroy(id)
+    }
+
     private external fun createInstrument(): Int
     private external fun setInstrumentWaveform(id: Int, waveform: Int)
     private external fun startNote(id: Int, frequency: Double)
     private external fun endNote(id: Int)
     private external fun setVolume(id: Int, volume: Float)
+    private external fun destroy(id: Int)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
index 8b1ba50..2b43524 100644
--- a/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/MonoInstrument.kt
@@ -49,4 +49,8 @@
             stop()
         }
     }
+
+    override fun destroy() {
+        internalInstrument.destroy()
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt b/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
index c6dae83..26e4fbb 100644
--- a/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
+++ b/app/src/main/java/com/lukas/music/instruments/PolyInstrument.kt
@@ -69,4 +69,10 @@
             }
         }
     }
+
+    override fun destroy() {
+        for (instrument in internalInstruments) {
+            instrument.destroy()
+        }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/lukas/music/ui/adapters/InstrumentViewHolder.kt b/app/src/main/java/com/lukas/music/ui/adapters/InstrumentViewHolder.kt
index b0ec2c5..3e129bc 100644
--- a/app/src/main/java/com/lukas/music/ui/adapters/InstrumentViewHolder.kt
+++ b/app/src/main/java/com/lukas/music/ui/adapters/InstrumentViewHolder.kt
@@ -60,6 +60,7 @@
                 val index = Instrument.instruments.indexOf(instrument)
                 Instrument.instruments -= instrument!!
                 adapter.notifyItemRemoved(index)
+                instrument!!.destroy()
             }
         }