This is because clean rooms in pickling are controlled contamination environments that allow for high levels of air and pure water, essential for the treatment of certain products. The water, made pure thanks to the use of a resin system for filtering, is essential for the final washing of the product which must not present atmospheric contamination. Ventilation, ventilation, materials used and operating procedures are regulated to control concentration and quality of the particles present in the air. The highly trained workers wear sterile and disposable gowns, caps and masks, thus guaranteeing the handling of each product that requires specific cleaning and hygiene conditions.