advice on styrene wraps to add rivet detail

[torikoos]

I love the loco's. However, on one of the pics, you quickly sprayed the entire loco steam power black, including the wheels. I just wondered what the quickest and easiest way is to remove the paint from the wheel surfaces so that you actually get electric pick up again? :-)
Reason I ask is that I have an old brass steamer that I was about to dismantle to take out the wheels prior to painting, but if you have a good trick that I haven't thought of yet, I'd gladly hear about that first :-) Thanks a bunch!