Thought I would share a good product I've found for doing some touch up bluing on steel. Using Birchwood casey perma blue paste. Quite easy to use for small jobs. Just degrease the metal (I use a small cloth and acetone). The paste goes on with a small cotton patch, rub in for 30 seconds and then clean off. Brighten up with some 0000 steel wool. Birchwood Casey Sporting Goods - Perma Blue® Liquid & Paste Gun Blue (https://www.birchwoodcasey.com/Refinishing/Metal-Finishing/Perma-Blue%C2%AE-Liquid-Paste-Gun-Blue.aspx) It does not make a uniform bluing but for stuff like my non-collector mauser here it cleans it up a bit. Also nice if you dont want to try and make molten salt in your garage.