The repair really is dependant on the damage and where it 's located. Usually dings can be smoothed to some degree with a flat faced smooth punch. The displaced metal is tapped back and the metal colored with the cold blueing compound. Rust is althogether a different matter. I prefer OxphoBlue as it will work thru a bit of oil and it is very tough! It may take several coats to match but follow the directions and it'll be like majic. It's available at Brownells... and get the liquid. I've not had a lot of luck with the creme..don't know why!!