Rustolium has to different primers. One for clean metal and one for rusty metal. You need to use the primer that's made for rust and it will work, but it's best to clean the loose rust as much as you can. Using just the paint or the clean metal primer won't do it. Also with the rusty metal primer you don't want to use it on non rusty areas unless you let it dry for a few weeks, perferablly in the sun. Otherwise the fish oil will just go to the surface of the paint and make it harder for the color paint to stick.