I'm considering order from reprolabels new labels for my G1 Ultra Magnus and G1 Optimus Prime. What's the best way to remove the old labels without harming the plastic? Acetone? I work in a body shop and the paint thinner would absolutely destroy the plastic. Also, what's the effect of replacing the original stickers on the value of the figures? Would I be better off leaving worn original stickers or would it be all the same with "aftermarket" stickers?