Masks cannot be used repeatedly? How to reuse masks correctly.

In a special period, masks can be difficult to find, so many methods of reusing disposable masks have recently appeared on the Internet. However, these methods cannot be blindly obeyed. I believe that everyone will be reluctant to bear the consequences of incorrect reuse of disposable masks. So today I summarize the methods of reusing masks suggested by relevant experts.

The thin medical surgical mask is divided into three layers. The outer layer has a water blocking effect to prevent droplets from entering the mask. The middle layer has a filtering effect. The filtering efficiency of the mask should not be less than 95%. The inner layer near the nose and nose is used to absorb moisture. Experts remind that the light-colored face of medical surgical masks is attached to the nose and mouth, and the dark-colored face is outward. Note that the part with the metal strip should be above the mask, do not wear it upside down. When wearing, distinguish between the front, back, upper, and lower ends of the mask, wash your hands, and hang the rope on the ears at both ends. Finally, press the metal strips on both sides of the bridge of the nose with your hands to make the upper end of the mask close to the bridge of the nose, and then stretch the mask downwards so that the mask does not leave wrinkles and covers the nose and mouth.

According to Dr. Ho Pak-Leung, a microbiologist and director of the Centre for Infection at the University of Hong Kong, He Suggested that once a surgical mask is worn, it may be contaminated by your own or other virus/bacteria as it contains saliva, nasal secretion and sputum. He shared that surgical masks are just like tissue paper, which are meant for single use. He gave an example that if you sneeze into a tissue paper, you won’t want to steam it or air dry it and then use it for a second time.

The doctor stresses that this isn’t a logical way of resolving the shortage of disposable surgical masks. He said that any attempt to reuse a mask may lead to self inoculation by the virus or bacteria on the surface. A WHO spokesperson has also commented that steam can potentially compromise the filter efficiency of the surgical mask.


According to the WHO, wearing a medical mask is one of the prevention measures to limit the spread of certain respiratory disease, however, using it alone is not sufficient to provide an adequate level of protection. They emphasised that if masks are to be used, the measure must be combined with hand hygiene and other infection prevention and control (IPC) measures to prevent human to human transmission of the 2019-nCov.

Recently, the Deputy Health Minister, Dr. Lee Boon Chye and said that those that don’t display any symptoms of the virus are not required to wear face masks as the virus is still contained from spreading. For those that are having fever, cold and cough, should wear masks while everyone else should continue to maintain good hygiene by washing their hands often using soap and detergent. He added that if you don’t wear masks properly and if you touch your face, there is still a risk of infection.

Feasible method:
1. Baking method: set the oven at 70 ℃, put the mask in and bake for 1 hour.
2. UV disinfection method, put the mask in the UV disinfection cabinet, and the sterilization time is 30 minutes to 1 hour.
Infeasible method:
1. High temperature and high pressure (pressure cooker) method will cause deformation of the mask and damage the air tightness of the mask.
2. The 75% alcohol (medical alcohol) method destroys the charged state of the mask filter material and affects the filter performance of the mask.
3. Microwave method. The mask and nose clip are made of metal.
Circumstance-based disinfection methods:
For the cooking method, if baking and ultraviolet disinfection methods cannot be used, N95 masks can be considered. The boiling water is used to cook for 30 minutes under water and completely dried. This method is not recommended for ordinary medical masks.

special reminder:
1. Disinfection and reuse of masks is an impatience under the shortage of materials. N95 masks may be used multiple times, but in principle, disposable medical masks are not recommended for repeated use.
2. After disinfection by the above method, if you find that the nose clip of the mask is not tight, or the air tightness of the mask is not as good as before, please stop using it immediately!
3. The disinfection method is only suitable for low-risk groups: not in high-risk areas, not medical personnel, not entering or leaving hospitals, and not touching patients
4. It is recommended not to use the disinfection method for densely-enclosed places where people enter and leave, and discard the masks after use.