[twobit]

I regularly use Ospho on bare or rusted metal before I prime and paint when working on trailers or other welding projects around the ranch. Ospho is that watery green liquid available at hardware and paint supply stores that you brush on bare metal. It is a rust converter, changing the metal to a black color.

Has anyone ever tried it on a blued firearm that has a few rust speckles on it? I thought about buffing with fine steel wool, applying Ospho, then lightly buffing again with steel wool before oiling the metal. Just wondering what it would do to the blueing? Trying to figure out a way to treat the rust freckles without damaging the rest of the blueing. Thought I'd ask before I try and find a spot on a old gun to experiment on.