Yes, for verdigris use Verdicare which works for mild verdigris. I know if you go to a dealer and want some nickels with green stuff I am sure you can find them in their lower grade bulk
V nickel bins. I saw a ton. I had one with a sheet of green stuff and it came off with acetone. Acetone works well on nickels and nickel is a hard metal that doesn't get harmed easily. I have a v-nickel with a sheet of green stuff on it and acetone took it off. I just peeled off.