Fixing up a rabbit cage?

I recently bought a new cage for our bunny and we wanted to use the old wire walls to set up as like a playpen out side of his cage. Now the problem is the bunnies chewed some of the coating/epoxy that is on the cage. I don't want it to get rusty so I was going to spray paint it or something but I don't know what I could use that would not heart the bunnies if they ate it. Any ideas on what I can use to re coat the wire cage???