Hi all...I need to clean some corrosion off of metal. The pieces in question are small, and fairly delicate (EKG leads). They look to be copper, coated with maybe nickel, though I'm not sure. The corrosion on them is that greenish-white stuff you see on old pennies and other copper pieces. Someone suggested using CLR to clean it...would that be too harsh? Any other readily-available products that would work in this situation?