The main hazard of disposable masks after washing is that they have no protection against viruses or the protection is greatly reduced, thus increasing the chance of contracting new coronaviruses or other viruses. Disposable masks are not reusable. The protective effect of disposable masks is mainly the inner and outer layer of the structure, which will generally be destroyed after washing. If you have to reuse it, it is not recommended to wash it. You can hang it in a clean and ventilated place or put it in a clean paper bag. In the current new coronavirus epidemic, it is recommended to use disposable medical masks and surgical masks, which are more effective in cutting off the droplet transmission of new coronavirus.