I use wheel acid... its sulfuric and hydrofluric acids deluted 4 to 1. I spray on lightly and wipe it with a cloth...sometimes rubbin it in a bit for tough spots. After its clean the surface will be dull, so i polish it up with a polishing compound...mothers etc. I know it sounds very aggressive but it seems to work on my centerlines just fine. you dont want to leave it on to long...anything over 30sec is to much. you can delute it 5 to 1 if you want aswell...its pretty strong stuff. I learned this from a paint and body guy that restores Shelby Mustangs. When I polish them, I dont use to high of a speed..medium speed seems to work best. When I did it..i tested it on the back side of the rim..off the car to make sure it would work...and it did just fine. I must say my rims were neglected for quite sometime before i bought the car...brake dust, tar, etc...all came off...and shined back up. ALLBRITE car care products is what i used.
