Thanks havoline and spudder. Might you know of a place where I can buy the products you are mentioning?

As havoline mentioned, use a wire brush and really clean it up good, remove ALL loose debris. I would use a product called POR-15, it will stop the rust from progressing. If the metal is thin you have minimal choices, either fill with bondo or cut and weld new metal in place. Whatever you do dont wait, treat it as soon as possible, like a cancer rust moves fast!

If your rust issues are only surface deep or scaling they you can wire brush the metal with a wire wheel on the end of a drill and treat it with off the shelf chemicals which you can find at any auto parts stores. If the rust has eaten away the metal then you have a bigger project on your hands. At that point you are cutting and welding new patch panels or panels removed from a parts car if they are not reproduced.