I did this with some good results, just used a diegrinder, sanding block, and some resin

I did the same with mine last fall. I also painted the exterior with some aluminum colored heat paint and painted the internals with some black heat paint. The painted surfaces are holding up well, but the tip faces will need some touching up once warmer weather returns. All in all, I've been really happy with the results. The silver colored cars need that little extra to make them stand out.