COVID-19 Mask Use & Re-Use

(Last Updated On: October 22, 2020)

Expert Guidance Plus Practical Tips… 

COVID-19 mask use poses a great dilemma.

COVID-19 mask

Someday, historians will look back on these days and try to explain them. They will ask, how did the COVID-19 mask, a simple accessory that saves lives, become such a potent political symbol? So potent that people refuse to mask, risking their lives just to advertise on their faces how they intend to vote?

I was pleased to see some attendees at a campaign rally in Muskegon, Michigan wearing face masks proudly emblazoned “Trump” or “MAGA.” The newsman apparently felt these folks were newsworthy because they were rare. (So rare that some felt obliged to explain that, no, they were not Democrats.)

My blogs have not been shy to recommend masks to those who care about themselves and their families, whatever their politics. As a scientist, I personally want to hear first from healthcare experts, those who know more than I do about risks to health. And then I will weigh their advice with that from economists and politicians in deciding how to best help myself and my family.

OK, end of sermon. This short blog describes some great advice recently published about COVID-19 mask use and re-use, for your and my practical benefit.

Here are the sections of this blog:

How COVID-19 Spreads

General Principles For Safety

COVID-19 Mask Re-Use

– Mask Comfort

– Paper Surgical Masks

Cloth Masks


How COVID-19 Spreads

Let’s start by summarizing today’s best understanding of the ways that coronavirus spreads, in descending order of importance:

  • Large droplets produced by coughing, sneezing, shouting, singing. Controlled by: mask wearing, social distancing.
  • Small droplets (aerosols) produced by breathing, talking, plus all of the above. Controlled by: fresh air circulation, air filtering, plus all of the above.
  • Touch transfer of contaminated body fluids (snot, mucus, spit, …). Controlled by: hand washing, hand sanitizing.
  • Viruses resident on surfaces (fomites). Controlled by: surface cleaning and disinfecting, placing objects in “quarantine” for several days.

The lower items on this list are significantly less important than the higher ones. In fact, given the number of infections traceable to super-spreader events, the second item listed may be as important as the first one.

General Principles For Safety

I’d like to suggest a few principles to guide a thinking person’s behavior:

  • Follow local government requirements. Social comity is a good thing to support.
  • Try also to follow local government recommendations. They are usually well-intentioned and informed by experts, even if for whatever reason they are not being required.
  • Take additional steps to protect you and yours. Those were discussed in earlier blogs (Aerosols, Groceries, Socialization, Workplace, Youth).
  • Spend little (or preferably no) time in places or with people where you feel pressured to act unsafely. That super-spreader event might be fun, but is it worth a visit to the ICU? As journalist Jeva Lange says, “just because you’re allowed back in the ocean doesn’t mean the man-eating great white shark that was in there is gone.”

As implied above, for various reasons government may recommend rather than require a precaution, even though infection experts passionately advocate it. For example, 80% of coronavirus cases are caused by super-spreader events that are facilitated by poor ventilation. However, CDC cannot even bring itself to instruct businesses to improve their indoor air quality. CDC’s mealy-mouthed guidance for office buildings merely asks employers to “consider” doing something, fourteen times!

COVID-19 Mask Re-Use

Yes, Americans are sick and tired of wearing masks even as virus cases are burgeoning, driven by bare faces. However, regardless of what the local rules say, it’s still true that the person who wears a mask reduces their own likelihood of catching a serious infection.

Because sensible people know that fact, the COVID-19 mask is not going to disappear overnight. So how can we make it less of an annoyance?

– Mask Comfort

Wearing a mask for an extended period is not pleasant. Pity the folks whose jobs require that! One’s face feels hot and sweaty, as if it is hosting a little incubator full of multiplying bacteria. And N95 masks? Bruise city!

One help, when and where permitted, is to pull the mask down beneath your chin when not needed. (Experts recommend against this if you are in the presence of active viruses, because then you’re wiping the virus-laden outside of the mask against your skin.)

Another approach is to change the COVID-19 mask frequently. So that you don’t despoil the planet by filling the landfills with used masks, you naturally want to be able to re-use your mask. And folks who seem to know tell us how we can re-use safely:

– Paper Surgical Masks

The N95 masks worn in emergency rooms provide good protection but they are very uncomfortable and difficult to safely re-use. The readily available three-layer paper “surgical mask” provides meaningful protection with much more comfort, and is safe to re-use if it is not soiled.

I found two articles that countenance re-use of paper masks. Both of them seem to be practical and sensible: one in Today and one from Sarasota Memorial Hospital. I will summarize the main points for your consideration:

  • Have 3 to 5 masks so you can rotate their use. It may be helpful to write a number inside each so you can rotate them in order. Plan to wear one for a day or less, then proceed to the next one.
  • Whenever a mask is visibly dirty, soiled or torn, discard it. Don’t attempt to clean or repair it.
  • To be safe, wash or sanitize your hands before and after handling a mask.
  • Remove the mask by holding the ear loops, without touching the potentially contaminated front surface of the mask.
  • Fold it once lengthwise with the (possibly dirty) front surfaces together.
  • Store the mask where it is protected from household dirt but open to circulating air: in a closed paper bag, or in a plastic bag which remains open to the air. You want the mask to to dry out, because the virus needs moisture to survive. Let it sit there in “quarantine” until it comes up in rotation again.

The principle behind letting a COVID-19 mask rest a few days before re-use is explained by epidemiologist Dr Lucian Davis of Yale: “Based on what we know about how long the virus can live on cardboard, which is similar material to paper, one would think that in 24 to 48 hours, those viruses would no longer be viable.”

– Cloth Masks

You may be one who prefers a cloth mask. Perhaps for its beauty, or variety, or clean look, or its environmental friendliness.

Cloth masks vary widely in effectiveness: two layers are substantially better than one, and three are somewhat better than two.

The Internet abounds with advice on how to launder a cloth mask. However, if it’s not soiled you could rotate several masks as described above rather than launder each after a single wearing. The virus becomes inactive on cloth as fast or faster than on paper.

Every mask protects others from your cough or sneeze. However, the mask only protects you if it seals well, so that you’re breathing through it rather than around it. To verify the fit, make sure that it snuggles against your skin when you inhale. Many cloth masks are not shaped to fit closely, or do not have a bendable stiffener to mold them close to your nose. Such masks short-change your safety for the mask maker’s convenience.


If you are under 25 and have no older family members to infect, your short-term health is pretty secure no matter what you do. But if you’re anyone else in our society, a COVID-19 mask may be a useful tool in your wardrobe. Wear a mask, somewhere, anywhere, and you may save a life. Perhaps, your own!

Image Credits:
– Vote mask adapted from Vote by netalloy and Mask by j4p4n on
Coronavirus illustration from CDC/ Alissa Eckert, MS; Dan Higgins, MAM at U.S. Centers for Disease Control


COVID-19 Mask Use & Re-Use — 8 Comments

  1. Excellent suggestions Art.
    I wear a paper mask all the time, especially when I’m at the gym. Even if it does not insure complete protection,anything that lowers and/or impedes the flux of viral particles is better than nothing.
    Be Safe, Paul

    • That’s a wise move, Paul. Fewer virions means weaker infection or no infection. It would also help if your gym lets in outside air and/or filters their air to cut down on aerosols. Art

  2. About “If you are under 25 and have no older family members to infect, your health is pretty secure no matter what you do.” there are some reports that a significant fraction (~1/7) of the people who are infected have rather loooong effects 8 weeks to 6 months. I heard this repeated in a recent BBC radio program, based on a study in England (I did not take notes).

    • Hi Metin, you’re exactly right. There is gradually increasing evidence that there are lingering long term effects from the coronavirus which may even affect people who had mild symptoms, or no symptoms at all. I don’t know the age distribution of the folks who have shown long term effects most strongly. I have modified the conclusion to say “your short-term health is pretty secure” which I confess is not a thorough answer to your comment. However, it hedges the conclusion a bit. What we need, and won’t have for a while, is a comprehensive model of how the virus affects people in the long term, and how that relates to measurable factors (non-virus medical conditions, which organs the virus affected, how large was the viral load, which immune responses occurred and how strongly, how the patient responded to specific therapies, and probably a lot more). CDC has an ongoing study ( as does WHO ( and they mention that young people are not immune from such effects, but so far I haven’t seen any study that quantifies the relative risk of young people for long term sequelae. – Art

  3. As usual very informative article. Thanks.
    I had the impression that I was wearing my mask to protect others. If I was infected (not according to a test last week) my mask would catch most of what I emit. The paper masks that I wear is not sufficient to keep out the virus, if virus is in the air, or infected person is across me emitting virus as s/he talks, coughs, sneezes is around me (although it may reduce it some unknown amount).
    Someone had made a very illustrative video of a mask reducing very effectively what may be emitted by a sneezing person. I do not know how to attach it here.

    • Thanks for your comment, Metin! The mask works both ways. Most casual transmission (excluding super spreader events) occurs via large droplets carrying the virus. People emit such droplets when sneezing, coughing, shouting, and, for some people, even when talking quietly and breathing. The droplets are large enough to be blocked by the infected person’s face mask. However, if you are wearing a face mask, your face mask will also block them providing that it’s well fitted, because the droplets are large enough to be caught by the mask’s pores. This is not just theory: my Herd Immunity blog quoted experiments with hamsters ( and a study in Australia (, both of which showed that although a face mask does not block everything, it definitely leads to a weaker infection even when worn only by the uninfected person. If infected people always wore a face mask, it would greatly reduce infections. But if they don’t, it’s all the more important that you and I wear one. [Aerosols can sail right through a face mask, but that is more of an issue during super spreader events (during which many participants wear no mask at all)]. Art

  4. Art, I forget how much I have mentioned it but second son Dr. Felix, has been involved all his working and student life with public health, at Oxford, then Harvard, then Imperial followed by WHO in Geneva, finishing up with Public Health England, this last decade or so. The position was so political that it was almost more than his job was worth to tell us too much of what was going on, but one thing he certainly was able to let us know right at the start, was that Covid 19 was far more infectious than most people realised and that it would spread very rapidly. Neither is he very optimistic about the pandemic over these winter months that are now upon us, but we wait to see.

    PHE was well understaffed from the start and he ended up working 7 days per week, 14 hours per day, in a rented hotel in London for his colleagues, and was given carte blanche to press gang members of other civil service departments to come to work for PHE. It seems the politics involved was pretty unpleasant and he was very relived to resign a couple of months ago and now works as a director NICE in charge of Data, and something else I forget. I thinks he is very relieved, now that Boris has inserted some old friend of his, the recently ennobled Dido Harding, to be in charge of PHE, under a new name, and with effectively no medical experience.

    So UK is still in a muddle over Covid with clamp downs starting up all over again but mainly in the Northern industrial towns. Life it otherwise quiet enough, here in the south Oxfordshire Chiltern hills, and most people do bother to wear masks which is compulsory in shops anyway. We have Brexit to worry over, following on the heels of your imminent election which is going to be exciting.
    I have been deliberating on a possible hypothesis that this sudden rapid change in circumstances through out parts of the civilised world that were formerly considered adequately well established to avoid serious concern over their future stability, but are now wondering why things suddenly have the appearance of falling apart.

    My presentment is that technology is moving ahead at such a pace that we cannot adjust our behaviour patterns rapidly enough to accommodate such rapidly changing circumstances. The mobile phone, with instant communication to vast amounts of information, with access to all recorded visual history in detail over the last century. It must present a huge change in the way we live and now exist, to which we have not yet become adjusted. If an effective stable and working quantum computer is finally achieved and developed, it seems quite likely to me that the results will accelerate the rate of change at an even higher rate, but maybe that might have some ameliorating effect. Who can say, but if so, then advanced technology might then find some way of resolving mental adjustments that I reckon are part of the current problems by which we seem beset.

    • Hello Nick, thanks for your comments and my sympathies to Dr Felix and his associates as they battle the virus both medically and in the world of public opinion. It’s amazing that despite the boggling advances in technologies of all types, nature still has very unpleasant surprises to spring on us. We all look forward to surviving 2020 and welcoming what we hope will be a better, more stable 2021. – Art