diff --git a/ClusterPrefab.cs b/ClusterPrefab.cs
index d8dd30b..ada3553 100644
--- a/ClusterPrefab.cs
+++ b/ClusterPrefab.cs
@@ -66,14 +66,17 @@ public class ClusterPrefab : ScriptableObject {
             MarkNuclei(visitedNuclei, output);
         //MarkNuclei(visitedNuclei, this.output);
         //Debug.Log($"Garbage collection found {visitedNuclei.Count} Nuclei");
-        this.nuclei.RemoveAll(nucleus => nucleus is Nucleus n && visitedNuclei.Contains(n) == false);
+        this.nuclei.RemoveAll(nucleus => visitedNuclei.Contains(nucleus) == false);
     }
 
     public void MarkNuclei(HashSet<Nucleus> visitedNuclei, Nucleus nucleus) {
         if (nucleus is null)
             return;
 
-        visitedNuclei.Add(nucleus);
+        if (nucleus.parent != null && nucleus.parent.prefab != this)
+            visitedNuclei.Add(nucleus.parent);
+        else
+            visitedNuclei.Add(nucleus);
         if (nucleus.synapses != null) {
             HashSet<Synapse> visitedSynapses = new();
             foreach (Synapse synapse in nucleus.synapses) {
diff --git a/Neuron.cs b/Neuron.cs
index f24eaa3..2f5e0f3 100644
--- a/Neuron.cs
+++ b/Neuron.cs
@@ -164,11 +164,19 @@ public class Neuron : Nucleus {
                 if (receiver != null && receiver.synapses != null)
                     receiver.synapses.RemoveAll(s => s.nucleus == nucleus);
             }
+        } else if (nucleus is Cluster cluster) {
+            // remove all receivers for this cluster
+            foreach (Neuron output in cluster.outputs) {
+                foreach (Nucleus receiver in output.receivers) {
+                    receiver.synapses.RemoveAll(s => s.nucleus == output);
+                }
+            }
         }
 
 
         if (nucleus.clusterPrefab != null) {
             nucleus.clusterPrefab.nuclei.RemoveAll(n => n == nucleus);
+            nucleus.clusterPrefab.RefreshOutputs();
             nucleus.clusterPrefab.GarbageCollection();
         }
     }