I refinished a pistol, years ago, with cold blue and got flamed for it. But I had a buddy who told me that heating the cleaned parts in the oven before applying the bluing compound would make a more durable finish and so it turned out to be. I hadn't planned on every refinishing another pistol but I picked up one fairly inexpensively (for Canada) because it was so bad! Only faint traces of nickel remained and it looked like someone had run a rag soaked in cold blue over the whole thing. The grips were badly fitted and the gaps filled with contact cement!!! I took all the old finish off which was a lot of work and time and very fiddly. Once I had it as polished as it was going to get, I sent it to a gunsmith who blued it for me. By doing the prep work the cost went from $600. to $70. Sadly, in the reassembly I broke the trigger return spring but thanks to some good friends, I'm awaiting parts that may resolve the issue. I'm attaching pics of what it looked like when I got it, disassembled, and partly reassembled. I will never do this again!