Just to say Big Mo I would tape off what I did not want painted clean the area good with like some 500 grit sand paper. If rust persist use 3part's water to one part vinegar and stainless steel wool on the rust. Let it stand for 15 minutes then Use stainless steel wool with clean water to clean it again. Let dry and prime. The solution will convert the rust. I have used this trick on most of my car in places. Maybe some one else will let you know just what to paint it with. I have used hot rod black which is an acrylic paint. Semi gloss. Use Rust Oleum rust converter you can get at lowes or some other hard ware store it works good. Then paint acrylic over that no problem.