Which is the best cold blue? Right now I have Brownells Oxpho blue. It works but it is not giving the results I am looking for. Has anyone tried Brownells 44/40 bluing? I used some birchwood casey once but all it ever did was rust no matter how much oil I put on the metal after bluing it. I even went so far as to soak it in clean 10w-30 motor oil for three days it still rusted. This was in California too so the humidity was no more than 20 to 30% maybe even less.