[Tom Line]

I would recommend removing every single painted screw and throwing them in the garbage. There are markings on the motor controllers themselves, and those screws can and will get accidently swapped around. I know this from experience. If you rely on screw color you WILL eventually kill a motor controller. It's not a question of "if", just a question of "when".

Get people used to looking at the markings on the motor controller. If you have trouble seeing them, paint those, not the screws. You'll be happy you did in the long run.