Everybody says "don't clean coins" but that one, like many of mine have been, is so shot that it's not worth anything anyway. My suggestion, above all else, is to use an electrolysis setup. It will destroy the patina and make it a pink-ish copper color, but it brings out details that will allow you to ID it probably pretty easily. I have done this on several completely slick coins where you couldn't tell the obverse from the reverse or see any detail whatsoever and I've been able to pull identifying features off of all of them and dates off of about half.any idea how to clean it?