Coffee, halogen lamp, some watercolor paint mixed up in the coffee. A tiny brush lets you concentrate the pigment on the indices, some sponging on the dial. Really hot halogen to dry it quickly lets you wet it with the sponge and move the pigment around more easily. Best thing is since it is all water soluble you can just rinse it all away in a sec if you don't like the look. If you want it permanent then you can hit it with water based satin poly spray.