Here's some Pictures of clad I cleaned with Conklin multi-surface gel. I've never tried CLR but sounds like good stuff as well. This stuff is $7 a pint. Very concentrated. I clean the coins first with just dish soap rinse off clean then re tumble with about a teaspoon of gel. These coin tumbled for about 4-5 hours. Found it at conklin.com. Some of these coins were orange from fertilizers. And all were very dirt stained some of the dimes still show some orange tint.