I went over it all with a heavy grit sand paper first. I think it was 40 or 60? Then we sand blasted some of it by hand that couldn't get in the corners well. Honestly, if we had better equipment, sand blasting it all would have been the ticket! Then the whole thing got a good wipe down with alcohol. After that, it was rattle cans. Again, lots of overspray, but it was also quite warm out when this was done. I'd suggest doing it section at a time, and do some kind of masking or backing to keep overspray down. Do some test tubes off car to see how it works since everyone sprays a little different. I used a fine sand paper to knock off any overspray that still remained, and resprayed over to clean up the surface. Again, turned out great and can't even tell where was touched up!