The best way to clean the casting is to mix the steel shot with steel grit, the steel grit which can be thrown to the corner, and the steel shot can be thrown to the flat surface, but also to avoid the surface of the casting is not smooth. Big grain steel shot impact the effect is good, but the number of particles per kilogram grain number is limited, covering rate is low, the sweep efficiency is not the highest, the surface roughness of steel shot impact of small, small particles per kilogram of steel shot cleaning effect is poor, but a higher number of particles per kilogram of steel shot, cover rate is high, can clean the small place, reduce the surface roughness value.