Be sure it is Cold Blue that you want. It is better to touch-up Rust Blue using weaker solutions (slow build-up, repeated applications) and then steaming over a pot on the stove with a foil funnel. (Or other steam source) This goes double for Damascus and Twist tubes.

Cold blue usually has Copper Sulfate in it, it actually leaves a coating. It's your decision, Oxpho-Blue from Brownell's is my choice, available in both liquid or paste.

Regards
Ken

Last edited by Ken61; 08/05/17 06:50 PM.
I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.