Is it actual metal, and not the plastic replicas that are so prevalent?

This will work for metal or plastic.

Use TSP to clean it, rinse, and paint with a alkyd based bonding primer. A~ heavy nap roller might be easier than a brush, but either will be a bit of a pain to be sure that you get into all of the texture. Then paint with an eggshell paint in white and allow to cure. Lightly sand down to the bare metal with a sanding block to be sure you're only hitting the high spots. (If it's plastic, this will be VERY tricky as you can sand all the way through to the plastic under the metal top coat very easily.) Mix a very light glaze and go over the whole thing, then wipe well. That antiques it to a more believable look rather than a "faux distressed" look. Then clear coast with a water based acrylic.

Thank you, GreenDesigns. Yup, it is actual metal. The glaze is great advice, and thanks for specifying what type of primer!