I know guys on here have had Alot of luck with I think red scotch brite and wd-40. I have accully wet sanded mine starting with like 400 grit sandpaper and went all the way to 2000 Or so it came out really good.
Jurt wd40 and scotched mine. Pretty impressive. My headers had a horizontal grain and going with it seemed to work best. I might have it chrome plated this winter.