The garage door is about 22 years old and needs a facelift. There are areas that look like rust although previously I thought the panels were aluminum. The person I hired to do the painting said there wouldn't be any rust if the panels really were aluminum so they must be painted steel. After cleaning (I have to do the prep work) do I have the painter use a metal paint, just an exterior paint, and does he have to prime the surface first. The only metal paint that I could find at the box stores was Rust O Leum which I have never been impressed with. Paint recommendations would help as I also have to do the shopping.