--- a/nashorn/src/jdk/nashorn/internal/runtime/WithObject.java	Thu Aug 22 18:46:26 2013 +0530
+++ b/nashorn/src/jdk/nashorn/internal/runtime/WithObject.java	Thu Aug 22 17:23:50 2013 +0200
@@ -73,7 +73,7 @@
     public boolean delete(final Object key, final boolean strict) {
         if (expression instanceof ScriptObject) {
             final ScriptObject self = (ScriptObject)expression;
-            final String propName = ScriptObject.convertKey(key);
+            final String propName = JSType.toString(key);
 
             final FindProperty find = self.findProperty(propName, true);