Funny, I
JUST finished restoring my over/under coin doors that I picked up for $20 each. The paint on them was flaking off and they were COMPLETELY RUSTED (I'm talking all brown). Here are the steps that I took:
- Removed all the hardware from the metal door. (by the way, the front pieces on mine are metal. Some are plastic, but metal is preferred since they are easy to sand down).
- I bought a "Strip Disc" attachment for my drill. It's what they use on cars for bodywork. It was $5.97 at Home Depot. That did wonders on the paint and completely removed the rust. In the tight edges, I used my Dremmel tool with a wire brush bit and then with a sanding bit. But if you don't have a Dremmel, you can sand it by hand with 500 grit sandpaper. (P.S. The one time that you don't wear gloves is when you accidentally sand your hand for that one split second that lasts for weeks - so wear gloves, goggles and breathe mask for the rust!)
- Once all the rust was removed, I took sandpaper to it and sanded it by hand all around for good measure. (some parts I sanded down to bare metal, others I didn't, I just made sure the paint wasn't loose or shiny anywhere)
- Then I washed them in the sink with soap and water to remove all the dust from sanding. I thoroughly dried them with a paper towel, then I let them dry for a few hours just in case. (You don't want to paint them with a wet spot somewhere).
- I used Rustoleum's "Hammered" spray paint in black. (#7215830 -
http://www.rustoleum.com/CBGProduct.asp?pid=29 ). What a perfect finish! Looks just like a real coin door should. It also hides any imperfections!
- I painted it, let it dry for 4 hours, painted it again, another 4 hours, final coat, let it dry for a couple of days.
- No need to prime with the Rustoleum brand (it says on the bottle it is unnecessary). It also can be sprayed directly over rust, so don't worry if you miss a couple of spots with your sandpaper.

** Also, I sanded (by hand) the inside of the coin return and spray painted that black too. At first I didn't but then I realized when you go to grab your coin after it's been returned, it looks great until you reach in and open the slot to reveal the ugly metal. So I had to take the whole thing apart to paint it. Just figured I'd save you some trouble.
Here are some pics of my final product (I forgot to take a "before" pic when it was rusted... sorry!

I also included a pic of the sanding bit and the paint can.