Refurbishing Gunmetal Watch Case

[Captain Shipton Bellinger]

I have a pocket watch with a 'gunmetal' case, which has obviously seen a lot of use. The case outer has worn to a dark grey colour and there is some light rusting where the back snaps on to the main case. The inside of the back cover and the dust cover are still the original lustrous black finish.

I'd really like to restore the case to its former finish but from everything I've read successful hot bluing (caustic black) is something of a dark art.

Is it worth me attempting this myself?