Got RUST? It's easy to remove, here's how.

[Bruce_in_Oz]

By "ceramic" I did not mean like your Granny's tea cup, but essentially a metal "oxide"

For example, Aluminium is soft, but its most common compound, Aluminium Oxide, is spectacularly hard and fairly inert. It is technically a "ceramic".

The entire point of blueing is not to make your guns look pretty, but to form a thin coating that, being porous, holds oil. The film of oil is what stops your toys going "brown and crunchy".

Parkerizing without the pre-blast will likewise produce dismal results on hardened alloy steels.

If you strip all of the oil out using some nasty solvent, the OTHER rust will appear frighteningly fast, especially if you live in Florida or coastal Queensland.

"Parkerising", which used phosphoric acid and a few additives, does the same. The difference is that successful "Parkerizing" requires that the steel surface be "activated", usually by grit or bead blasting.

If you bead / grit blast and then "blue", you get a lovely satin / matt BLACK finish.

Parts made from "interesting" modern alloys that have been hardened by heat treatment may need this "pre-treatment", by blasting; otherwise they will come out of the blue tank looking like THAT book: ........Fifty Shades of Grey................, or purple, or whatever.

Parkerizing without the pre-blast will likewise produce rather pallid results on pretty much any steel.