suggest you try M.A.A.S. metal cleaner/polish made in Ohio.....available somewhere in Wal Mart. Chuckle, I've even used it to polish inside reloading dies and on patches to run down a bore. Kinda surprised on what I got out of my bore. Chuckle, can remember a post on the Surplus Rifle website, made by someone prepresenting themself as being with MAAS, suggesting it would be good to use to polish a rifle chamber.