Q & A on Masks and Covid19

Most face masks are disposable and are for one-time use only. Ideally, face masks should not be used once they are soiled or the inner lining gets moist. Rarely they can be sterilized for limited reuse. If you want to reuse the mask, it should be kept dry so that it can last long. While taking out the mask please do not put it under the chin so that germs there will not attach to the mask. Please don’t leave used masks on any surface as it will be a source of infection. It should be properly stored so that it can be reused.

Reuse – refers to the practice of using the same N95 respirator for multiple encounters with patients but removing it after each encounter. It’s stored in between encounters to be put on again.

  • Cloth mask – Can be properly washed, disinfected, dried and reused.
  • Surgical mask – If it’s dry and the layers and shape are intact, put it in a zip lock pouch with a desiccated gel. The gel absorbs moisture and keeps the mask dry. If the mask is intact and not torn, it can be reused for 3 days. If it’s worn by an infected person, it should never be reused or shared.

Extended use of N95 Masks

The CDC reports that prolonged N95 mask use (including between patients) can be safe for up to 8 hours, and encourages each user to review each manufacturer’s recommendations prior to following this strategy. Current guidelines encourage wearing a face shield over the N95 to decrease the chances of soiling the mask.


Because coronaviruses lose their viability significantly after 72 hours, many organizations have promoted a rotation and re-use strategy. Assuming there is no soiling and minimal to no viral contamination to the mask, the CDC suggests that masks can be re-used up to 5 times with the following strategy:

Mask Rotation

Acquire a set number of N95 masks (at least 5 per the CDC), and rotate their use each day, allowing them to dry for long enough that the virus is no longer viable (> 72 hours). Proper storage for this technique requires either hanging the respirators to dry, or keeping them in a clean, breathable container like a paper bag between uses. Make sure the masks do not touch each other, and that you do not share your respirator with other people. A user seal check should be performed before each use.

Importantly, when planning to reuse an N-95 mask, practice fastidious donning/doffing to avoid contamination of the inside or outside of the mask at all times (see below methods for donning and doffing). If the mask is damaged or significantly contaminated from aerosol-generating procedures or bodily fluids, the CDC recommends discarding it.


Mask decontamination strategies are actively being investigated by the CDC, mask companies, and large academic/industry collaboratives. General principles of re-processing include:

  1. The method must sufficiently inactivate the viral load on the mask.
  2. The mask cannot be soiled (bodily fluids, makeup)
  3. The filtration capacity and electrostatic charge must be preserved as much as possible.
  4. The fit of the mask cannot be compromised.

How to dispose of a used mask? (Remember masks should be treated as medical waste)

Different germs can survive on a used mask for different durations. Experts feel that viruses, when left exposed, can survive between a few hours and a few days. My earnest request to all of you is not to throw the used mask indiscriminately in lifts, parks, workplaces, homes, open dust bins as it can pose a potential health hazard to people who come in contact with such masks. Also, some people are picking them up for re-use and hence putting their life in danger. The infected masks have respiratory secretions on them and can be dispersed and transmitted through the air. So, please be sensitive. Always wash your hands before and after taking off the mask.

  • Cloth mask (Wash) – Should be washed properly and frequently and left to hang and air dry.
  • Surgical mask (Fold, tie, wrap) – It should be removed chin upwards and please take care to remove it from the strings and be careful not to touch the front portion while taking off the mask. After taking the mask off, please fold it half inwards, such that droplets from mouth and nose are not exposed. Then, fold the mask into another half, until it looks like a roll. The mask can also be wrapped with its ear loops so that it will not unravel. Then wrap the mask in a tissue paper or polythene bag and immediately discard it in the yellow waste bag. Keep the things handy before disposing it off.
  • N95 respirator – When removing the mask, hold the edge of the straps attached to take of the N95 mask. Don’t touch the inside part of the respirator. Wash hands before and after it. Gently remove the mask so as not to disseminate contaminants on the mask. Place the mask in a plastic bag or zip-lock bag. You can also store them in a breathable container such as a paper bag between uses. Secure the bag tightly. Place the plastic bag into garbage can or biomedical waste disposal unit. Never put on a new mask until you have properly washed your hands.