i just dyed my proto grippers and they turnd and grey-ish green. and the core did go grey. they were white or yellow on silver and now they are grey-green on grey. looks like poopy. =(
liquid dye does work just leave them for 14 of so hours and then let them dry without washing or rubbing the dye of the wheel, so put a stick through the wheel and blance it between to things and leave them until the wheels arnt wet and you get no dye on your fingers