Nope just wax away using a good quality carnuba wax and or paint sealent. Cheap waxes may stain rubber, vynile, or the like. But normaly they just wipe off with ease.
I have a white mach. I gove over the decals like they are not even there. If u have alot of buildup then your using to much product. Make sure you are out of the sun or u will have a hard time getting the wax off...