Birchwood Casey offers the perfect solutions for restoring and maintaining your firearm's finish with their Perma Blue line. Whether you're touching up scratches, worn spots or completely rebluing your gun, these products provide a non-streaky, even blue-black finish for steel (excluding stainless). Perma Blue Liquid Gun Blue is ideal for a quicker, uniform finish, while the Paste Gun Blue takes a bit longer to darken, resulting in a denser, richer finish. It's important to note that while both products work on most metals, they do not blue stainless steel, aluminum or other non-ferrous metals. For optimal results, ensure the metal is thoroughly cleaned and free of rust before applying either solution.