Originally Posted by D&H 65:
Tamiya makes several "clear' colors for coloring bulbs. I just dip the bulb in the jar up to the metal base and then place it in a carboard holder to dry. I know they have at least green, red, blue, & yellow.
You could probably spray them (airbrush), but I never took the time to try that approach.
I've done this with the same Tamiya Acrylic Clear colors, but it takes me several dips to get a decent coat on the bulbs.