1. Sand and other impurities need to be removed first. Generally, water guns or other cleaning equipment can be used for cleaning. At the same time, cleaning agents or solvents can be used to clean the surface oil stains and other substances, so that the surface is completely dry.

2. Secondly, for heavier sand, grinding treatment is needed. Generally, the surface is polished by mechanical equipment such as sandpaper or grinding wheel.

3. After the final polishing treatment, phosphating treatment is needed again. Before phosphating, the surface needs to be thoroughly cleaned and dried. When phosphating, you can choose to soak the sample in acidic phosphating solution for a certain period of time to form a phosphating layer on its surface.