diff --git a/Source/Heap.m b/Source/Heap.m
index fbe7da027..1508d2869 100644
--- a/Source/Heap.m
+++ b/Source/Heap.m
@@ -76,7 +76,7 @@
   _contents_array[0] = _contents_array[_count-1];
   decrementCount(self);
   [self heapifyFromIndex:0];
-  return ret;
+  return AUTORELEASE_ELT(ret);
 }
 
 - addElement: (elt)newElement
@@ -84,6 +84,7 @@
   int i;
 
   incrementCount(self);
+  RETAIN_ELT(newElement);
   for (i = _count-1; 
        i > 0 
        && COMPARE_ELEMENTS(_contents_array[HEAP_PARENT(i)], newElement) < 0;
diff --git a/Source/LinkedList.m b/Source/LinkedList.m
index c33781085..e2fb4be76 100644
--- a/Source/LinkedList.m
+++ b/Source/LinkedList.m
@@ -119,7 +119,7 @@
   [[oldElement.id_u nextLink] setPrevLink:[oldElement.id_u prevLink]];
   [[oldElement.id_u prevLink] setNextLink:[oldElement.id_u nextLink]];
   _count--;
-  return oldElement;
+  return AUTORELEASE_ELT(oldElement);
 }
   
 - insertElement: (elt)newElement after: (elt)oldElement
@@ -160,18 +160,20 @@
       [oldElement.id_u setPrevLink:newElement.id_u];
     }
   _count++;
+  RETAIN_ELT(newElement);
   return self;
 }
 
 - (elt) replaceElement: (elt)oldElement with: (elt)newElement
 {
+  RETAIN_ELT(newElement);
   if (oldElement.id_u == _first_link)
     _first_link = newElement.id_u;
   [newElement.id_u setNextLink:[oldElement.id_u nextLink]];
   [newElement.id_u setPrevLink:[oldElement.id_u prevLink]];
   [[oldElement.id_u prevLink] setNextLink:newElement.id_u];
   [[oldElement.id_u nextLink] setPrevLink:newElement.id_u];
-  return oldElement;
+  return AUTORELEASE_ELT(oldElement);
 }
 
 /* End of methods that change the instance variables. */
diff --git a/Source/RBTree.m b/Source/RBTree.m
index 17fdc64a7..718550eb5 100644
--- a/Source/RBTree.m
+++ b/Source/RBTree.m
@@ -237,7 +237,7 @@ static id nilRBNode;
   [oldElement.id_u setLeftNode:[self nilNode]];
   [oldElement.id_u setParentNode:[self nilNode]];
   _count--;
-  return oldElement;
+  return AUTORELEASE_ELT(oldElement);
 }
 
 /* Override methods that could violate assumptions of RBTree structure.