For a long while I have greatly admired a Engravers work (Kiselev engraver) and the art he creates on Zippo lighters, recently he was asked how he goes about the different coloring as it is not inly copper etc and his answer was very vague. I have been researching how to color metal with not much success until stumbling across gilding paste , currently experimenting with that. anyone have any other methods? thank you all in advance