Anything help copper?

sinin1

to get rid of small green spots? - mineral oil for 3 years?

Everyone says do not dip copper in jewelluster -> is there anything that can take a small layer off without wrecking the coin (even worse than it is because it is already a wrecked coin)?

poptopsRus

Blue Ribbon (especially the old stuff with the Trichloriethane in it) can sometimes help take old green corrosion off of copper. Good luck.

Libertad

I have used Arm & Hammer washing soda (in the laundry detergent section) with aluminum foil with some limited success on verdigris spots on Buffalo nickels. They're 75% copper.

Use a pyrex or ceramic cup, place aluminum foil in cup, add a thin layer of the dry washing soda granules, place coin, add more washing soda, and a bit of foil over the top. Pour boiling water in the cup, and wait for all the fizzing to stop. pour off the water.
Pour in more boiling water, fizz/etc. until granules are pretty well gone. The aluminum foil turns sort of dark, and fragments a bit.

Fresh verdigris is reduced pretty well, older stuff is lightened, but still pretty adherhent since it eats into the surface with time. A touching of Blue Ribbon with a q-tip helps significantly.