I live in North Alabama so surface rust isn't really issue but after 24 years plus some paint booth over spray, it was apparent on my frame. I will one day do the frame the right way when it is stripped away from the rest of the truck, but for current my solution I plasti-dipped the entire front wheel wells and frame with 2-3 coats. It's held up well for two years now, and it has seen its fair share of mud, salt, grime, soap, and pressure washers. It certainly isn't the shiniest or most protective stuff (its a real matte/flat black), but then again we're talking about a place where the sun-don't-shine, and I really don't have to worry about rust here. And whenever it wears off I can just do it again for another two years for $10-15 worth of the plasti-dip. Again, I know this is NOT the best or correct way to do it, but if you're just looking for an eye-candy, cosmetic touch up its the easiest and cheapest thing you can do. It's also one of those things that literally no one else will notice except you, but you will love the way a fresh coat looks.