Don't clean it. Coin collectors don't want cleans coins. But it's yours, so you do you. Should contain silver. Not looking it up, rn. Bowl, aluminum foil on bottom, place coin on foil, near boiling water over it, add baking soda. Chemical reaction cleans it for you, less scrubbing. Scrubbed coins are scratched up. Already collectible, it's also worth it's weight in silver. (Look that up to confirm and how much 80%, 90%?)