I'm not really sure.Maybe I'll write a book on the subject and I'll sell you one-haha.I see another ramble coming on but I can't now.First check out the sections Scott has on his main site.If you're talking from the very start,is it a car or bike?On bikes I strip them unless I'm redoing aftermarket parts I already did.Then I go back to my bodywork the best I can.On a car it gepends if you already have a sound finish and if it's original or has been painted a few times.