User blog comment:ToaFairon/Sharpies/@comment-24510871-20100708202204

Spray painting is much better than using a sharpie. If you want to colour a dark mask, it just won't work. Whereas with spray painting, you can pretty much colour the whole thing.

Sharpie:- Pros- Cons-
 * Easy to remove (cotton + nail polish remover)
 * Cannot colour on dark pieces
 * Tricky to colour hard-to-reach places

Spray paint:- Pros- Cons-
 * Can colour almost anything
 * Can colour almost anywhere
 * Smell for a bit
 * Hard to remove
 * Takes a while to dry (depends on what you buy)

But what ever you do, don't colour in ball joints, the colour will rub off when you move the piece.