Like J.W. said, and you can go to Radio Shack, and get their etching acid, (nitric acid) And you can wax the blade, and then scratch out your design, name, etc. and also you can dip the clean blade in the acid, and let it sit a a few minutes, and then clean it off, with water, and baking soda, and it will have a mottled look to the blade.
Seen some at a rendezvous, and that is how the guy said he did it. I have not tried it myself yet, but I am wanting to try it. It could be used for a lot of things, that you want to be a little different looking, like hilts, finger guards, buttons, butt plates, etc..
Wayne