1. According to the processing requirements, some parts need to be polished, and the surface shall be free of machining burrs;
2. Degrease all parts;
3. Pickling and passivation shall be carried out after degreasing, and the cleaning agent does not contain phosphorus;
4. After pickling and purification, rinse it with purified water, and there shall be no reagent residue. This step is omitted for carbon steel parts;
5. Wipe the parts one by one with non-woven cloth, and do not leave the surface of the parts with wire wool, or blow dry with clean nitrogen;
6. Wipe the parts one by one with non-woven cloth or precision filter paper dipped with analytical pure alcohol until there is no dirty color.