Cold bluing is not particularly resistant to holster wear, nor does it provide a large degree of rust resistance. Often it does provide an adequate cosmetic touch-up of a gun's finish when applied and additionally oiled on a regular basis.

Can you blue over rust?

To many, the answer is surprisingly – NO! If bluing is just worn and there is no apparent active red rust, Rustblue can be applied directly over it and will blend the old with the new and render a uniform texture. ... I have restored many firearms blued by the rust blue method and by caustic bluing or the hot water method.

Is hot bluing better than cold bluing?

Although a very slow process, cold rust bluing produces a deep blue color generally considered to be the most durable kind of bluing. ... By contrast, hot-water bluing processes can produce a deep blue finish in just a couple of hours, rather than several days.