diff --git a/src/main/java/io/netty/buffer/api/NativeMemoryCleanerDrop.java b/src/main/java/io/netty/buffer/api/NativeMemoryCleanerDrop.java
index 5e448d2..68c4c1f 100644
--- a/src/main/java/io/netty/buffer/api/NativeMemoryCleanerDrop.java
+++ b/src/main/java/io/netty/buffer/api/NativeMemoryCleanerDrop.java
@@ -61,9 +61,9 @@ class NativeMemoryCleanerDrop implements Drop<Buf> {
         var mem = manager.unwrapRecoverableMemory(buf);
         var delegate = this.delegate;
         WeakReference<Buf> ref = new WeakReference<>(buf);
-        AtomicBoolean gate = new AtomicBoolean();
+        AtomicBoolean gate = new AtomicBoolean(true);
         cleanable = new GatedCleanable(gate, CLEANER.register(this, () -> {
-            if (gate.compareAndSet(false, true)) {
+            if (gate.getAndSet(false)) {
                 Buf b = ref.get();
                 if (b == null) {
                     pool.recoverMemory(mem);
@@ -84,7 +84,7 @@ class NativeMemoryCleanerDrop implements Drop<Buf> {
         }
 
         public void disable() {
-            gate.set(true);
+            gate.set(false);
         }
 
         @Override
diff --git a/src/main/java/io/netty/buffer/api/SizeClassedMemoryPool.java b/src/main/java/io/netty/buffer/api/SizeClassedMemoryPool.java
index b015064..dc547e1 100644
--- a/src/main/java/io/netty/buffer/api/SizeClassedMemoryPool.java
+++ b/src/main/java/io/netty/buffer/api/SizeClassedMemoryPool.java
@@ -70,7 +70,7 @@ class SizeClassedMemoryPool implements Allocator, AllocatorControl, Drop<Buf> {
                 Send<Buf> send;
                 while ((send = v.poll()) != null) {
                     try {
-                        dispose(send.receive());
+                        send.receive().close();
                     } catch (Exception e) {
                         capturedExceptions.add(e);
                     }
@@ -86,12 +86,16 @@ class SizeClassedMemoryPool implements Allocator, AllocatorControl, Drop<Buf> {
 
     @Override
     public void drop(Buf buf) {
+        if (closed) {
+            dispose(buf);
+            return;
+        }
         var sizeClassPool = getSizeClassPool(buf.capacity());
         sizeClassPool.offer(buf.send());
         if (closed) {
             Send<Buf> send;
             while ((send = sizeClassPool.poll()) != null) {
-                dispose(send.receive());
+                send.receive().close();
             }
         }
     }