He's NOT really a "gun guy" but he does fancy himself to be a "handy guy" and thus does a lot of his own repairs around his home and on his vehicles, etc. In this case he has a 1960's vintage Marlin .22 rifle and would like to RE-BLUE it. I told him that for spot refinished a cold blue might work just fine but to do the whole rifle and have it look GOOD, I'd take it to a 'smith were it mine. What say y'all? Because this is way outside of my expertise. I told him I'd send him a link to the responses posted here. He's a really good guy. Old friend of mine. Good conservative Christian guy.