Birchwood Perma Blue Liquid Gun Blue is the best way to touch up scratches and worn spots or even completely reblue most guns. It will give a non-streaky, even blue-black finish to steel (except stainless). Perma Blue will not blue stainless steel, aluminum or non-ferrous metals.
Specifications:

Type	Perma Blue Liquid
Size	3 oz
Quantity	1
Bristle Type
Length
Includes
Material	Multiple
Tip Feature
Battery
Thread Pattern
Protects
Suitable For	Firearms
Eco-Friendly