Lots of white, some cyan to add to that mybe draw some nice circuits on them, maybe just add more runes and curses with every available stroke.
Then again, I'd draw on them with my hands, more fun that way, a finger smears the paint, a crude and primal design ~

And obviously there would be magic involved. What good is giving someone new markings if they can wash them off and the markings don't stick within Purple One's scales?
Maybe there's some colours which change said kobold's temperament, maybe there's a womb tattoo to draw onto their lower belly to make them horny and desperate to be filled by a potent male? Who knows! Way too many options!