How to Clean, Reuse or Hack a Coronavirus Mask


The CDC recommends wearing a face mask that covers your nose and mouth when leaving your home for essentials like groceries and prescriptions. Some types of masks are not intended for reuse, but there are a few things you can do to sanitize them, upgrade filtration and extend their lives. Here are some strategies that will help you get the most out of your mask, and keep you and your family safe. 

Let’s say you just got back from the grocery store wearing your mask. Now what?

1. Treat your mask like a biohazard.

Isolate it from the rest of your family. “You don’t want to be leaving it on the kitchen counter or the coffee table where other people may inadvertently be handling it,” says Kirsten Koehler, an associate professor of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health.

2. Wash your hands with soap every time you remove or even touch the mask.

Act as if the virus is on both sides of the fabric. Make sure to wash your hands properly for at least 20 seconds.

Those are coronavirus mask basics.

There’s much more to know, though, if you want to extend the life of your gear or even make your own mask.

How to clean homemade cloth face masks and the best material to make one

To clean your mask, run it through the washing machine and dryer after use. The water doesn’t necessarily needs to be hot but make sure to use a laundry detergent. 

If you don’t have access to a washing machine, you can hand-wash using soap. Another option: Put the mask into a paper bag and leave it in a warm place for at least two days.  After that, the virus will become inactive and won’t be infectious.

When you are wearing a homemade mask, you should keep in mind that you are not wearing the mask to protect yourself, but to minimize the spread of virus particles to others. Even if you feel no effects, you may be asymptomatic.

Homemade masks are less effective at protecting the wearer because most have voids, or spaces near your nose and cheeks where the tiny droplets can be inhaled, and the pores in the fabric alone are generally not small enough to trap tiny aerosolized droplets.

Some materials make better masks than than others. According to a study published in Disaster Medicine and Public Health Preparedness, homemade masks made from a kitchen towel proved to be the most effective at removing particles.

On the other hand, T-shirts or pillowcases may be the best choice as they can provide a better fit by stretching. Avoid using old fabrics because washing and drying may stretch the pores, allowing more particles to get in. 

The choice of fabric is very important. Professor Koehler suggests using tightly woven fabric folded in multiple layers. A research paper published in PeerJ confirms the fabric concern. The study looked at the surface of 20 different types of cloth masks and found the size of pores in masks ranged from 80 to 500 micrometers. For comparison, the novel coronavirus is about 0.12 micrometers:

You may also want to avoid thick materials like vacuum cleaner bags. A material with high resistance will force air to escape through routes around the mask fabric creating a void. Also, breathing through a thick mask can be tough on your heart and lungs. This could put elderly people and those with preexisting cardiopulmonary conditions at risk.

“It shouldn’t be so difficult that you just can’t physically breathe, but you should notice some resistance in your breathing,” Dr. Koehler said. “Otherwise your mask is probably not doing anything.”

Adding any sort of filtering inside the mask may help to reinforce it and add additional protection. An engineer specializing in aerodynamics has tested the effectiveness of paper towels. A single layer captured 23% of particles 0.3 microns or larger. Adding an extra layer increased particle capture to 33%.

Phillip Clapp, a postdoctoral researcher at the Center for Environmental Medicine, Asthma, and Lung Biology at the University of North Carolina, has been testing various homemade masks. When he studied three layers of cotton fabric, he saw that the material itself had efficiency of around 90%. However, once he wore the mask made from that material, its efficiency dropped below 50%.

“And what that tells us is that it really has to do with how well that mask will fit your face, as to how well you’ll be protected,” Dr. Clapp said. 

The mask should cover both your nose and mouth. The CDC has published several tutorials on making face masks, which include masks with elastic ear loops as well as tie strings. If you choose to make a mask with tie strings, it’s important to make sure the straps fit correctly around the head so the mask does not fall down.

When wearing a mask, secure the bottom ties first with a bow around the nape of your neck. Then, pull the mask by the upper ties over your mouth and chin and secure around your head.

Preliminary results from a study by researchers at Northeastern University show that sewn fabric masks can in some cases approach the filtration efficiency of commercially produced masks.

Adding an elastic outer layer improved fit for all mask types tested. Particularly helpful was adding an outer layer made from nylon stockings. Even surgical masks were found to perform better with stockings during the study.

You should not clean an N95 mask at home. But you can reuse it with proper care. Here’s how:

The general public is asked not to purchase N95 respirators due to shortages in the medical supply. But if you have one, they offer good protection. The key with the N95 respirator is proper fit: There should be no air gaps or voids around the nose, cheeks or chin.

According to Koehler, some data suggests that the virus could live on N95 respirators up to seven days, as opposed to about two days for the cloth fabrics.

She recommends using a method that isolates the mask in a breathable location:

Never use cleaning products such as Lysol, alcohol or bleach. Liquid, including soap and water, can damage the mesh of electrically charged fibers designed to catch particles and droplets.

Can you use expired face masks and respirators?

Expired N95 respirators remain as effective as the new ones, Clapp said. He tested respirators that were as far as 11 years behind the expiration date. While the respirator may still filter particles as good as new, elastic bands that may deteriorate. 

Can you clean and reuse disposable surgical masks? Sort of. Here’s how:

Surgical masks are intended to protect the wearer’s face from large droplets and splashes of blood and other body fluids. Efficiency of surgical mask filters can range from less than 10% to nearly 90% depending on the manufacturer and the type of the mask. According to Clapp, surgical masks with ear loops (38.9% effective) performed worse than surgical masks with tie strings (71.5% effective.)

Generally, surgical masks are less effective than N95 respirators because they don’t provide a seal around the nose and mouth, which could allow smaller droplets to get in. At the same time, studies show that they are better than homemade masks at protecting from  larger particles. 

Ana Rule, an assistant professor of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health, recommends not buying surgical masks to ensure enough supply for health care workers. Wear one only if you have it already at home. 

How to reuse: The best strategy is to isolate it for a week in a breathable container such as a paper bag. Putting masks in the plastic may lead to accumulation of moisture and development of bacteria. Surgical masks should not be washed, because liquid damages the filter.

How to clean and reuse elastomeric respirators

When elastomeric respirators are properly fit tested and worn, they can provide the user with an effective face seal and will hold up to repeated use, cleaning and maintenance. As with N95 masks, use only if you already have one.

How to clean and reuse the respirator: Wipe down with alcohol swabs to disinfection after each use. The attached filter cartridges are replaceable and are easily changed. Though they can be reused, their life span depends on many factors such as exposure and concentration of particles. It’s important to double check if the cartridges you have are designated for filtering coronavirus particles.

Using masks in the family

The best practice is just for one person within a family to go to a store or other places where it might be difficult to maintain social distancing. Parents should ensure that children don’t touch their face, because wearing the mask may encourage them to do so. CDC recommends that children under 2 years old shouldn’t wear the mask because of the risk of suffocation.

This article originally appeared on USA TODAY: Coronavirus masks: How to clean, sanitize and reuse your mask