Hey i used Worcestershire sauce on the 1 i found recently cleaned it up real nice, there is a post in the cleaning section that showed a before and after picture for this method. Not my post but i had the same results if not better, i checked the coin hourly until it was where i wanted. Heres the link hope it helps ya.
I have used the worchester and also Dale's. The only thing I did extra was after removing it and getting how I wanted it, I mixed some baking soda and water to clean it off. I just wanted to make sure to get all the salt off that I could. This procedure worked pretty good.