This material comes with both a clean gloss finish, and a gungy gloss finish.
This material has been set up in Cycles and Corona with both glossy maps plugged into an adjustable MixRGB node. Simply slide the MixRGB factor from 0 to 100 to get either a grungy or clean finish!
Height map can be used with experimental mode in Cycles using adaptive subdivision. For Corona, displacement nodes are not supported so please use a displacement modifier to create real geometry using the height map.