We used to use muriatic acid (available at pool supply places) to get all the paint, rust and even grease off of parts. If you leave it on too long, it will also pit the metal some. Problem of course is that you have to wear alot of personal protection gear (glove, splash guard, respirator etc), the toxic fumes, and the disposal of the stuff, but it works great. you can add it to a bit of water to decrease the acidity (always add acid to water, never the other way) Let it dry out for a while in a *dry* (low humidity) environment, and primer/paint as desired. If there is too much metal damaged, weld in some extra and then grind it down flush.
Erik
