The claim that you can shake off carcinogens by shaking the mask before wearing it is false. Masks made by legitimate manufacturers do not contain carcinogens. Masks are usually sterilized with ethylene oxide during the manufacturing process, and ethylene oxide is indeed a toxic carcinogen that can be used to make fungicides and is widely used in industries such as laundry, pharmaceuticals, and printing and dyeing. However, the masks are usually tested for ethylene oxide content on the masks before leaving the factory, and they can only leave the factory and go on the market if they meet the national standard. Therefore, the masks worn by the public every day are safe for use. Masks with substandard production may contain carcinogens, in which case the carcinogens will not be shaken off even if they are shaken off before wearing. Therefore, wearing substandard masks is not recommended. It is recommended that the general public can change the mask once a day according to the usage. If you want to remove it in the middle, you can find a clean paper towel to wrap it up or hang it up. If the mask is wet or contaminated, it needs to be replaced immediately.