The St. Francis Hotel in SF has been washing their coins for a long time. Click on this link to watch how they do it. (you have to watch a short commercial in the video before you see how it's done.)
http://cbs5.com/goodquestion/coin.wa....2.798317.html
I often have dreams about finding money, mostly coins, and I'm scrambling to pick up as many as I can before anyone else notices them. I always wake up before I can spend any of it.