[Neweller]

My suggestion would be to remove the racks, clean them really good to make sure there is absolutely no grease or grime using a course steel wool pad. For additional etching and as a adhesion promoter use a good rust inhibiting self-etching primer following the instructions. Follow up with a good epoxy finish coat (appliance type will work) available at your home improvement store or online. Make sure it is well cure before installing the back in your fridge. West Marine carries everything you need as well and it's a very reasonable refinishing task.

If you have never used steel wool pads, here is an example of the one's I buy made by 3M and they come in a pack of (6) for only about $6-7 dollars. You can go the cheaper route and buy the other type but these are nice.