Like other materials exposed to the atmosphere, stainless steel can also become dirty. If the waste stainless steel is dirty, it cannot be sold at a better price. However, waste stainless steel on dirty surfaces can be treated through methods such as rainwater flushing and manual flushing.

The effect of rainwater scouring is determined by placing the same Flat noodles directly in the atmosphere or in a covered place. The effect of manual washing is determined by manually scrubbing the right side of each Flat noodles every six months with a sponge dipped in soapy water. The results show that the removal of dust and siltation on the surface by rain washing and manual scrubbing has a good effect on the surface condition, compared with the Flat noodles placed in the shed and the place not to be washed. It is also found that the condition of surface processing also has an impact, and the effect of Flat noodles with smooth surface is better than that of Flat noodles with rough surface.

Therefore, the interval time for washing is influenced by various factors, with the main influencing factor being the required aesthetic standards. Although many stainless steel curtain walls are only washed when wiping the glass, generally speaking, stainless steel used for external purposes is washed twice a year.