On another thread, a member recommended using VerdiCare to remove verdigris from coins. This product gets rave reviews and was developed by a chemist.
I have a coin I may be using it on but I don't think I have any that need it...except maybe one...knock on wood. Now I have a few brass tokens that really need it!
Wizardcoinsupply.com sells it. I think my old LCS sold it...but I may be mistaken. @BadThad makes it.
I think you must mean that you don't mind greenish patina on a bronze? (a corrosive chemical reaction which destroys the surface is never a good thing, unless you are a serial killer) Ummm, or maybe I'm mistaken? => I've always thought that verdigris = bronze disease? (but I just read that verdigris is a protective coating?) ... sometimes this coin-stuff is too hard!!