diff --git a/rhc/database/db.py b/rhc/database/db.py
index 800d7ef..ad966ac 100644
--- a/rhc/database/db.py
+++ b/rhc/database/db.py
@@ -22,7 +22,6 @@
 THE SOFTWARE.
 '''
 import pymysql
-import threading
 
 
 class _DB(object):
@@ -55,7 +54,7 @@ def setup(self, dirty=False, database_map=None, commit=True, close=False, delta=
         return self
 
     @property
-    def  delta(self):
+    def delta(self):
         ''' only specify changed columns on update '''
         return self.__delta
 
diff --git a/rhc/database/test/test_basic.py b/rhc/database/test/test_basic.py
index c5ad997..eea72ef 100644
--- a/rhc/database/test/test_basic.py
+++ b/rhc/database/test/test_basic.py
@@ -1,5 +1,6 @@
 from __future__ import absolute_import
 import pytest
+import weakref
 
 from rhc.database.dao import DAO
 
@@ -103,3 +104,22 @@ def test_join(data):
     assert len(names) == 2
     assert 'fred' in names
     assert 'sally' in names
+
+
+def test_dao_cleanup_from_save(db):
+    obj = Parent(foo=1, bar=2).save()
+    ref = weakref.ref(obj)
+    assert obj is ref()
+    obj = 0  # dereference
+    assert ref() is None
+
+
+def test_dao_cleanup_from_load(db):
+    # save object and remember id
+    obj_id = Parent(foo=1, bar=2).save().id
+    assert obj_id
+    obj = Parent.load(obj_id)
+    ref = weakref.ref(obj)
+    assert ref() is obj
+    obj = 0
+    assert ref() is None