Originally Posted by brianinc-ville

If you search around here on "oxalic acid," you'll see a lot of discussion; personally, I tried it and didn't think it was miraculous enough to justify the toxic waste it produces. Others have had good results with other acid solutions. Me, I'll stick with bronze-wire brushes, on the Dremel for small stuff and on an electric drill for bigger parts. Bronze wool pads are also excellent (look for them at marine-supply stores).