diff --git a/pytools/persistent_dict.py b/pytools/persistent_dict.py
index 9afcb65373de8c08fe6da83e01b9e8910f33db86..06e0f00334b791bcbc7dd94d225c22603db92783 100644
--- a/pytools/persistent_dict.py
+++ b/pytools/persistent_dict.py
@@ -356,7 +356,6 @@ class _LRUCache(collections.MutableMapping):
 
     def clear(self):
         self.cache.clear()
-        del self.lru_order
         self.lru_order = _LinkedList()
 
     def __setitem__(self, item, value):