I was gonna post something along that line,Check out the lump of Spanish coins I posted pics of(Look for Feds and Metal detector depth, probably a couple of pages in by now) That was cleaned using Electrolysis, usefull for OLD salt water silver you want to preserve. Too complicated to explain in a short post. Your other clad stuff is easy as pie. FIRST REMOVE THE ZINC PENNIES!!! No Aluminum JUNK!!! JUST COINS!!!! IMPORTANT!! Go to the hardware store and buy a bottle of Muriatic Acid (plumbing section). Put all your coins in a PLASTIC container. DILUTE THE ACID BY 1/2!!!!!!!! with tap water. Pour over the coins to cover and let sit a few hours or over night. This should be OUTSIDE CAUSE IT STINKS and will rot the electronics in your house!!!!!You then put the container in the sink and let hot tap water run into it until all acid is gone.Put one tablespoon of BAKING SODA in the hot water and mix well.Let sit for an hour and rinse/dry your coins. This will kill any remaining acid.The coins come out gun metal grey (except the pennies) and if you like them shiny you have to tumble them in a commercial tumbler from a gun shop(used to clean brass shell casings for reloaders). Most time I just spend them the way they are, no tumbling. Works well for me!!