Paint is not resistant to friction. Krylon does not work. Rustoleum does not work. Duplicolor vinyl dye that "sinks into the plastic" does not work. Sanding is practically useless since the buttons move their sockets, if you notice, they will still rub against the sides and cause friction, therefore stripping paint. Also, whenever you use your nail to hit a button, you chip paint (start button). The paint will chip within a few days, weeks, or months, if you are very lucky.
There must be a way to physically stain the plastic material. The fact that I have about 6 sets of buttons laying around all chipped up makes me want to throw s***, especially when I have a bad day. You have to strip the paint and repaint only to receive the same inevitable effect.
As you may tell, I have not had the best of days, but I hope you guys can save yourselves some frustration and NEVER PAINT YOUR BUTTONS. Until myself or someone else figures this bs out.