diff -r 53a7c2226a2b Lib/concurrent/futures/thread.py
--- a/Lib/concurrent/futures/thread.py	Fri Oct 19 07:37:56 2012 +0200
+++ b/Lib/concurrent/futures/thread.py	Fri Oct 19 11:13:51 2012 +0100
@@ -63,6 +63,7 @@
             work_item = work_queue.get(block=True)
             if work_item is not None:
                 work_item.run()
+                del work_item
                 continue
             executor = executor_reference()
             # Exit if: