Index: comments/block_comments.php
=========================================================
--- comments/block_comments.php	(revision 1.10)
+++ comments/block_comments.php	Mon May 17 11:18:02 WST 2010
@@ -56,4 +56,10 @@
         }
         return $this->content;
     }
+    function instance_delete() {
+        global $DB, $PAGE;
+        //delete orphan records
+        $DB->delete_records('comments', array('contextid'=>$PAGE->context->id, 'commentarea'=>'page_comments', 'itemid'=>0));
+        return true;
+    }
 }