The cleaning and sterilization of N95, KN95, and cloth face masks is likely to increase since many are now utilizing this form of PPE. 

Due to limited supply, healthcare workers and regular people alike may need to reuse their face masks.  This article will shed some light on various types of face masks and how to clean them from virus contamination.

Use the links below to navigate to a specific section in the article. Updated August 2020.

How to clean and decontaminate cloth face masks.

Cloth face masks should be washed frequently. The California department of public health recommends after each use or daily. 

Cloth masks should be laundered using detergent with hot water and then dried on a hot cycle to kill bacteria and microbes.  

Basically, hot soapy water is the key.  Soap is able to break down the protein coat of the virus and is very effective. 

If you must re-use your mask before you are able to wash it, it is recommended to wash your hands immediately after putting it back on and to avoid touching your face. 

Here are some general guidelines for cloth masks from the California Dept. of Public Health:

  • Face coverings can be made out of cloth, factory-made or hand-sewn, or improvised using bandannas, scarves, T-shirts, sweatshirts or towels.
  • The material should cover both the nose and mouth.
  • Ideally, face coverings should be washed after each use. Dirty masks should be placed in a dedicated laundry bag or bin.
  • Use detergent and hot water when washing cloth masks, and dry them on a hot cycle.
  • Be sure your mask is comfortable; you don’t want to have to keep adjusting the mask, because that means touching your face.
  • Wash your hands, or use hand sanitizer, before and after touching your face or face coverings.
  • If you must wear your cloth face covering again before washing it, wash your hands immediately after putting it back on and avoid touching your face.

Discard or get rid of cloth face coverings that:

  • No longer cover the nose and mouth
  • Have stretched out or damaged ties or straps
  • Cannot stay on the face
  • Have holes or tears in the fabric

Do cloth masks protect against viruses such as COVID-19?

Cloth masks do not give the wearer full protection against viruses in the air, but they can help protect others by barricading biological aerosols or “droplets” containing the virus.

This is especially effective in cases where asymptomatic people (infected people who show no symptoms) may be releasing the virus without knowing it. 

A Cambridge University study from 2013 found that homemade cloth masks significantly reduced the potential amount of infectious droplets expelled by the wearer.

While cloth masks aren’t perfect, they go a long way in “flattening the curve” during a  pandemic and are far better than zero protection. 

Can you clean surgical masks or reuse them?

We could not find any recommended cleaning procedure for the blue style of surgical masks.  These masks cannot be washed since washing them may damage the mask.

Typically, surgical face masks are strictly for a single use; however, may in theory be disinfected using UVGI as mentioned above.

The CDC has the following recommendations for limited reuse:

  • The facemask should be removed and discarded if soiled, damaged, or hard to breathe through.
  • Not all facemasks can be reused.
    • Facemasks that fasten to the provider via ties may not be able to be undone without tearing and should be considered only for extended use, rather than re-use.
    • Facemasks with elastic ear hooks may be more suitable for reuse.
  • HCP should leave the patient care area if they need to remove the facemask. Facemasks should be carefully folded so that the outer surface is held inward and against itself to reduce contact with the outer surface during storage. The folded mask can be stored between uses in a clean sealable paper bag or breathable container.

N95 and KN95 Face Masks: Can you reuse N95 or KN95 face masks?

If possible, it is always recommended to replace N95 or KN95 face masks.

In times of limited supply, the CDC has the following recommendations for extended use and limited reuse of N95 masks:

  • Minimize the number of individuals who need to use respiratory protection through the preferential use of engineering and administrative controls;
  • Use alternatives to N95 respirators (e.g., other classes of filtering facepiece respirators, elastomeric half-mask and full facepiece air purifying respirators, powered air purifying respirators) where feasible;
  • Implement practices allowing extended use and/or limited reuse of N95 respirators, when acceptable; and
  • Prioritize the use of N95 respirators for those personnel at the highest risk of contracting or experiencing complications of infection.

If extending the use of face masks, the following steps should be taken to reduce contact transmission after wearing:

  • Discard N95 respirators following use during aerosol generating procedures.
  • Discard N95 respirators contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
  • Discard N95 respirators following close contact with, or exit from, the care area of any patient co-infected with an infectious disease requiring contact precautions.
  • Consider use of a cleanable face shield (preferred3) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls) to reduce surface contamination.
  • Perform hand hygiene with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).

If reusing face masks, the CDC also recommends the following steps to reduce contact transmission after wearing:

  • Discard N95 respirators following use during aerosol generating procedures.
  • Discard N95 respirators contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
  • Discard N95 respirators following close contact with any patient co-infected with an infectious disease requiring contact precautions.
  • Consider use of a cleanable face shield (preferred3) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls), when feasible to reduce surface contamination of the respirator.
  • Hang used respirators in a designated storage area or keep them in a clean, breathable container such as a paper bag between uses. To minimize potential cross-contamination, store respirators so that they do not touch each other and the person using the respirator is clearly identified. Storage containers should be disposed of or cleaned regularly.
  • Clean hands with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).
  • Avoid touching the inside of the respirator. If inadvertent contact is made with the inside of the respirator, discard the respirator and perform hand hygiene as described above.
  • Use a pair of clean (non-sterile) gloves when donning a used N95 respirator and performing a user seal check. Discard gloves after the N95 respirator is donned and any adjustments are made to ensure the respirator is sitting comfortably on your face with a good seal.

Masks should only be extended or reused by same wearer since asymptomatic wearers could potentially spread infection.

How long can you reuse N95, KN95 or surgical masks for?

Keep in mind, most face masks are intended to be used once and replaced as needed. Due to the limited supply, the CDC has a list of recommended reuse methods.  You can find these methods listed above. 

How long you can reuse a mask for is something that is not specified by the CDC. Therefore, how long you reuse your mask dependsden on your personal comfort and a few other factors. 

Please advise, the following is merely a suggestion for how long you can reuse different types of masks and not reviewed by any medical studies or evidence. 

If you are frequently cleaning your mask, it will begin to deteriorate just like many other materials would and will affect how long you can use your mask. 

Rather than an exact count for how many times a mask can be reused, we can provide a guideline.

If you notice any deterioration of your mask, it should be discarded. You should thoroughly inspect the mask after each use and cleaning. Pay special attention to how well the mask is fitting—if your mask straps begin to lose elasticity it will no longer cover your face effectively and should be discarded.

All full list of CDC recommendations can be found here.

How to clean and disinfect N95 and KN95 face masks. 

Proper disinfection and decontamination of N95 or KN95 face masks is tricky business. You need to inactivate the virus without compromising the filtration and fit of the mask.

KN95 and N95 face masks are usually replaced after each use when plenty of supplies are available. Unfortunately, there is a very limited supply of N95 masks due to the pandemic.

Even with the FDA approving KN95 face masks for use, supplies are still limited. 


GET KN95 MASKS ON SALE BY CLICKING HERE


Other than the CDCs recommendations for extended use and reuse, there isn’t much “peer reviewed” information available on decontamination of N95 face masks. 

That doesn’t mean there isn’t any…

The Society of American Gastrointestinal and Endoscopic Surgeons list a few key principles for effectively cleaning face masks. 

  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 ionic charge must be preserved as much as possible.
  4. The fit of the mask cannot be compromised.

Several decontamination methods for inactivating the COVID-19 virus exist that show promise. 

How to decontaminate N95 masks using vaporized hydrogen peroxide.

Researchers at Duke Health recently looked into sterilizing N95 face masks by means of vaporized hydrogen peroxide.  Using “specialized equipment” in their biocontainment laboratory, they successfully decontaminated N95 face masks.

The vaporized hydrogen peroxide was able to permeate the mask layers and kill microbes without deteriorating the mask.

Not every hospital has this technology available to them unfortunately, but there are other potential methods of sterilization below. 

Keep in mind none of these methods are endorsed by the CDC or the mask manufacturers; however, due to the severity of the current crisis may be helpful. 

How to clean N95 masks using dry heat.

One study performed by the University of Tennessee performed a variety of tests using heat and suggested that heating a mask at 70C for 30 minutes can provide decontamination while preserving filter integrity. 

Tests at the National Institutes of Health utilizing SARS-CoV-2 specifically indicated that this method can be used for two cycles to kill the virus without compromising good fit. Research efforts are ongoing and this is not yet recommended by the CDC.

How to clean N95 masks using UV light.

Another method, already in use by some hospitals, uses UVGI (Ultraviolet Germicidal Irradiation) to kill Corona Viruses.  In a recent, non-peer reviewed study, N95Decon found promising data to indicate that UV-C light can effectively render COVID-19 inactive. 

This was performed under specific dosing measurements and adequate light penetration onto the surface material, or FFR, of the masks. 

This seemed to be one of the more promising methods provided the entire surface of the mask and straps could be dosed with adequate amounts of UV-C.

However, N95Decon admits that ”UV-C and other deactivation approaches should be viewed as risk mitigation for extraordinary circumstances rather than complete decontamination.”


A key takeaway from this study was the ability to effectively bathe all exterior surfaces of the mask with UV-C light—previous studies showed residual traces of virus even after decontamination had been performed, likely due to limited exposure of the entire surface area.

You can find more on this in our article about whether UV light is helpful when used in HEPA filtration devices.

How to clean N95 masks using moist heat.

Moist heat (heating at 60-70°C and 80-85% relative humidity) has been shown to be effective for flu viruses, but is likely not a feasible option for decontaminating N95 masks since it can affect the filtration ability of the mask. This method is currently not recommended by the CDC.

Methods that are NOT approved by the CDC for cleaning N95 masks.

  • Alcohol
  • Baking
  • Bleach
  • Boiling
  • Ethylene oxide
    • May be toxic to the wearer
  • Microwave
    • At-home microwaving is not recommended because of variable power settings, and metal portions of the masks may catch fire.
  • Sanitizing wipes
  • Soapy Water

Can you wash a N95 mask or a KN95 mask?

The short answer is no…

There are two things you should definitely NOT do with any N95 or KN95 mask:

  • Spraying or wetting with aerosol or liquid alcohol.
  • Washing in soapy water.

N95 face masks which have a paper outer and inner layer should not be boiled, steamed, or washed because they will disintegrate the filer medium material.

Doctor Tsai of UT Knoxville performed a study that showed significant reductions in mask filtration efficiency when cleaned with alcohol or soapy water. So make sure not to use either of these methods. 

If your mask is not made of the paper like outer and inner material you can potentially boil it. 


According to Dr. Tsai: “submerging an N95 in 125C/260F degree steam or boiling water for 3 minutes will disinfect the mask without significantly reducing its filtration efficiency (FE). Don’t excessively stir the mask if you boil it, use only enough manipulation to keep it submerged.

As is with many things in life, proceed with caution. 

N95 vs KN95: What is the difference between N95 and KN95 Face Masks?

N95 face masks are examples of personal protective equipment, or PPE, that are used to protect the wearer from airborne particles and liquid contaminating the face.

They are regulated by the FDA and NIOSH (U.S. National Institute for Occupational Safety and Health). The N is for “Not resistant to oil” and the 95 refers to the minimal is efficiency level at 0.3 microns (of which is it 95% efficient).

Similarly, KN95 masks are also a form of PPE used to protect the wearer from similar hazards though they are not regulated by NIOSH. These masks are often identical to N95 masks and are the “N95 equivalent” for medical usage in China. 

In the US, they are primarily used in industrial settings and offer the same filtration as N95 face masks with a rating of 95% at 0.3 Micron. In fact, these masks are often produced from the same assembly line as N95 masks however are not sent for NIOSH regulation.

On April 3rd of this year, the FDA approved the use of KN95 masks for healthcare professionals in an effort to increase the available PPE face masks and lower the spread of the COVID-19. 

Resources linked throughout the article. 

Where can I buy FDA approved KN95 face masks for sale?

FDA approved KN95 masks are for sale here for a reasonable price.

View PPE products here.