Acetone will neutralize organic materials but doesn't adversely affect metal. Just rinse with distilled water after the acetone and dry well before storing. Don't scrub or harshly rub the coin when drying.
Nice find!

Edit: use high grade acetone. Things like nail polish removers have additives that CAN harm the coin.
"Nummi rari mira sunt, si sumptus ferre potes." - Christophorus filius Scotiae
Edited by Bump111
08/01/2017 11:12 pm