Speaking of spots on copper ...

TwoKopeiki

Any idea what the white stuff is? It seems to disappear in acetone, but when I take it out and the coin dries - the white comes back. I don't want to try ammonia just yet, since it strips patina if applied incorrectly.



Thanks!

lordmarcovan

I don't know what it is, but try some Vaseline (petroleum jelly) on it. That probably won't remove it, but Vaseline (or oil) might give it the "wet" look you are getting when using the acetone.

Or you could go "old school" and lacquer it.

1jester

What you see is verdigris residue after an acetone dip. Acetone removes organic contaminants, but if there's verdigris on copper, the end result after an acetone wash will be this white residue. You could oil the coin (with Blue Ribbon, for example) and hide this white stuff. Or you could try an extended olive/mineral oil soak to try to remove it, but in most cases verdigris likes a long-term relationship with your copper coins.