Easy instructions:
Grind / Steel Brush / Sand to clean metal
Clean off area with Wax and Grease Remover, you can even use lacquer thinner if you want, but be sure to wipe it clean and wipe off with clean rag.
Spray primer, make sure it is a fill primer even if it's the rattle can stuff. Lay a thin coat first, let it flash, spray a second coat laying it down thicker, flash again and wait a few minutes, then hit one more time with primer. This gives you a good sandable surface. Wait long enough to let the primer completely cure, if you have a garage and some type of heat lamp, or the garage is about 70 degrees or so, you might be able to work on it in a 3-4 hours. The key is to let the solvent evaporate out of the primer.
Wet sand (preferable) or at least scuff off the top "skin" of primer. Sand as smooth as you want using 400 grit wet / dry sandpaper, or if you are just going to top coat to protect, then just use a scotch pad and scuff off the skin of the primer. If you were doing finish type work, you might use "Red Cap" a thickened primer that is pressed onto the surface with a rubber surface. That stuff should be sanded with 220 grit, and followed with a coat of primer to give the best result.
Top coat, use any kind of paint that's compatible with your primer, i.e. don't use krylon primer and follow it up with some other company paint. Check what the primer and paint are made with, typically don't mix ketone based paints on top of non-ketone and vice versa. Usually you can use a Rust-O-Leum primer and top off with a Rust-O-Leum paint.
Once you are ready to get it painted, point out the spots to your paint man and let him know what you used there.
Hope this helps
