Been searching all over the web now and I am just trying to find out what this process is called. I see it in a lot of old movies. Guy puts a lighter to his iron sights to hide the shine of the metal for a night raid etc. Is this something grunts used to do cause it was easy and fast, and no one does it any more? I tried it on a knife blade and it looks kind of cool if I can make it consistent. Obviously it wipes right off, but is it safe to leave there? Will it prevent rust? Will it exacerbate it? Haven't ever used this on a firearm, but I am curious if you all have, and if so, what you refer to this as when you do it...

Cheers

Smoking the sights. Soot is deposited onto the sight to reduce glare or shine. Highpower shooters do this for matches, carbide lamp works well.

Rubs off easily, I would imagine the soot doesnt offer much in the way of rust protection.