Hello! i'm working on weathering a bunch of my cars, starting with trucks. Whats a good color for the wheels and trucks? the wheels have me most confused. i don't know hat kind of paint would look right on them. I know that polly scale oily black would probably work on older car trucks with the journal boxs ( full of coton wast dipped in oil, which is why the wheels turn black) but newer roller bearing trucks have me lost. I'm not sure what pain mixture would work for them. I'm also trying to figure out how to get some trucks on locomotives like my GG-1 to look weather right. they seem to have this dirty look on the, but i cant recreate it... any advice?