I used some enamel to paint mine. I used the kind you get at hobby and craft stores for painting models. It worked extremely well, but be advised that if you go this route, you'll need to make sure it cures a couple of days before using it. Enamel paint dries pretty quickly, but it can take a week or more before it cures enough to use without scratching. Once it's fully cured, it's pretty rugged paint though.
In any case, you'll want to make sure to clean the old surface as best you can, and use a paint that will adhere to metal, or use an appropriate bare metal primer.