>>11363196Hey! See:
>>11359386and
>>11360883That's really all the nitty-gritty on rebluing with cold blue. Just remember, the cold blue will never be as deep or as durable as hot bluing. Ever. That's because you're not actually forming an iron oxide on the surface, you're just making a deposit of a compound that looks very similar. It's honestly a pale comparison to REAL hot bluing, but it will do in situations where the metal needs to be protected with something, ANYTHING, and a blued look is preferable.