Flitz metal polish paste removes tarnish, rust, water stains, chalking, lime deposits, heat discoloration, lead and powder residue, oxidation, bugs, tar, oil, fingerprints, tree sap, bird droppings, graffiti, dye, and black streaks.
All of my S&W pistols had factory-polished feed ramps and chamber throats, but I have polished feed ramps on other makes. I applied Flitz metal polish paste to a dremel buffing wheel and buffed the ramps and chamber throats until they were mirror polished. Flitz is a very fine abrassive which will polish metal, but it won't change the shape of your feed ramp. This always did very well for me.