Not sure how to clean nor would I clean it with out being sure I would not do any damage. You may want to post the coin and question under coins and see if someone there answers you or after that in General Discussion and see if anyone there can tell you in no good answer in coins. I wouldn't take a chance since it has been buried that in cleaning you may remove some of the detail or scar up the surface if the wrong method is used. Good Luck and Congrats on the finds!