I have been using carnauba wax, ment for autos, with some very fine abrasive in it, on my hunting and carry guns for maybe 10+ years. It is especially good on my old hammer doubles that I use for duck and goose hunting -- best waterproofing for metal I ever used. NONE of these guns have especially good bluing left, having been hunting or working guns for decades and decades, two since 1890. These guns get wet many times each season.

I simply lather some on, wipe it around a bit, let it dry, then wipe excess off with soft cloth, no buffing (these are hunting guns, so not much shine wanted).

For bragging guns with better finish, pure carnauba with no abrasive at all should give peace of mind about possible premature wear on finish. For working guns, careful selection of carnauba auto wax might be quite OK, even better than OK.

Niklas