After trying every exhaust bluing removal product known to man I finally found one that really works. Its called Blue Job. Its a fine powder that you mix with water and rub on the blued section. After rubbing for less than a minute the dark blue area was almost gone and the chrome shine underneath revealed. I have never seen anything like it- this stuff works, and works well. I ordered online from them after I googled Blue Job chrome polish and went to their website. It is sort of expensive, but since it works so well, I think its money well spent.