68 barracuda 383s "Driver Paint Resto"

where there is pitting in the metal, and I have cleaned it best I can with DA and wire cup, I like Ospho, a phosphoric acid type cleaner, $30/ gal US found at Ace hardwares et.... but realize it is an acid and some epoxies can react with it I am told. I never had this problem though.
paint co. like DuPont ( I have used) have their metal cleaners that work well bt are very expensive. I suggest always try these "solutins" on a spot and see how it all works out.