diff --git a/extra/oset/_abc.py b/extra/oset/_abc.py
index 228e526fa..d3cf1b51e 100644
--- a/extra/oset/_abc.py
+++ b/extra/oset/_abc.py
@@ -467,10 +467,9 @@ class OrderedSet(MutableSet):
             return len(self) == len(other) and list(self) == list(other)
         return set(self) == set(other)
 
-    # causing "Exception TypeError: TypeError('list indices must be integers, not NoneType',)"
-    # in garbage collection phase
-    #def __del__(self):
-        #self.clear()                    # remove circular references
+    def __del__(self):
+        if all([KEY, PREV, NEXT]):
+            self.clear()                    # remove circular references
 
 if __name__ == '__main__':
     print(OrderedSet('abracadaba'))
diff --git a/extra/oset/pyoset.py b/extra/oset/pyoset.py
index ea3d3709f..2a67455bc 100644
--- a/extra/oset/pyoset.py
+++ b/extra/oset/pyoset.py
@@ -76,9 +76,8 @@ class OrderedSet(MutableSet):
             return len(self) == len(other) and list(self) == list(other)
         return set(self) == set(other)
 
-    # causing "Exception TypeError: TypeError('list indices must be integers, not NoneType',)"
-    # in garbage collection phase
-    #def __del__(self):
-        #self.clear()                    # remove circular references
+    def __del__(self):
+        if all([KEY, PREV, NEXT]):
+            self.clear()                    # remove circular references
 
 oset = OrderedSet