(1) In the cold working process of optical components and lenses, after the bottom plate is cleaned, the remaining abrasives (CeO2, rare earth powder, kaolin, etc.), coolant (tap water, emulsifiers, etc.), auxiliary materials (wax, asphalt, insects, etc.) Glue and other protective paint), organic solvents (gasoline, kerosene), etc.

(2) In the process flow of components and lenses, fingerprints, saliva, and sweat may be caused by the operator's contact.

(3) During the storage of components and lenses, dust and impurities in the air, carbon dioxide, temperature, water vapor, etc. cause "corrosion" on the surface of the glass workpiece.

(4) All kinds of dirt attached to components and lenses during all related processing. The above-mentioned dirt often does not exist alone, but penetrates each other. With the influence of the external environment (temperature, humidity), it will also be oxidized and decomposed or corroded by the action of microorganisms, forming more complex compounds that adhere to the surface of the element, or even corrode the surface of the element. , The formation of stains that are difficult to remove.