Depending on how large of an area I have a trick that worked for us. I found this out on my dads black SRT-6. His had some bad spotting, almost etching everywhere on his car. On the chrome emblem I used Mothers Chrome polish, worked great. After hand rubbing Finesse It by 3M, it got 90% off the paint. Sooo, I used a very little bit of the Chrome polish on a CLEAN damp micro-fiber towel on the paint, worked great. I would not pour a bunch on your roof and go to it. But on small detail areas it worked great. After that Please use Zymol auto polish. If you follow the directions on the bottle, (Its a pain) I've never ever used anything that works as well.