Inkahootz

You can use linseed oil. Bring your work to a black heat, soak a cloth in the oil and start scrubbing. Beware though... YOU NEED GOOD VENTILATION !!! Leaves the work an aged black. Can be slightly sticky though.

Nice one.

I also made a helmet as an apprentice, however turned it into a letterbox.
The back opens, and you put the mail through the slit.

Really expected some local kids to try to work it over with big bungers...but really
... 8mm steel isnt going to budge.