Birchwood Casey offers you the best ways to touch up scratches and worn spots or even completely re-blue most guns. It will give a non-streaky, even blue-black finish to steel (except stainless). Both Perma Blue Liquid Gun Blue and Paste Gun Blue provide great bluing to metal that has already been thoroughly cleaned and is free of rust. Perma Blue Paste Gun Blue is slower to darken than Liquid Gun Blue, but will build up a denser finish. All backed by Westlake Market's quality product guarantee.