De anodizing will remove the protective plating and render the parts more prone to corrosion. But for R/C cars it probably does not matter. Ace hardware sells greased lightning - a cleaner that will take off anodizing better than anything. Oven cleaner works too, but is smelly and dulls the alum. If you just want a new color, prime and paint it. Test the paint on something else with some nitro fuel to be sure it will hold up.