The best way to do it is as Tony described. The quickest way to do it is as Oly described.
I used Zero Rust on my chassis with good results. For your application, though, you probably want something you can paint over, and I don't know how ZR will do there. Corroless is a similar product, but it is supposed to act as a primer--I know a few people who have painted over it with decent results.
However, IMO, you will get the very best results by doing as Tony says.
Ed
