So I got this copper heater-core from a junk yard, right. Now I wanna' get all of this green azz corrosion off of it. How do I do that? Someone suggested using CLR on it. Someone else said hydrogen peroxide?!?. There was an article on this site at one time suggesting boiling with some other chemical, but I'm in an apartment and don't have the space or equipment to boil it and I'm not certain that that was to remove corrosion as much as just dirt and grime.