I like slow rust bluing instead of cold blue. It's an involved process though and it pays to do some homework. I did this to the rock hammer I restored for my geology field work and it looks very nice. I took it on my field course this summer. I'll post some pics sometime and you can get an idea what it looks like after six weeks of hard use digging and bashing into rocks. Much more wear than an axe should ever see. The finish has worn, but the look seems authentic to me and provides corrosion resistance. Areas that see wear tended to stay clear of rust from abrasion anyway so I think it's a viable option.