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Electric cooker an easy, efficient way to sanitize N95 masks, study finds
- asperous 6y agoThe main thing is consistency, as ovens/cookers are temperature controlled. Other bootleg options are available: Household clothes driers can get hot enough as well, but not all of them do. Cars on a hot day can also get to the desired 140-150f+ range. Many dishwasher sanitize cycles as well https://www.who.int/csr/sars/survival_2003_05_04/en/ https://www.who.int/csr/sars/survival_2003_05_04/en/ https://dailyhomesafety.com/does-dryer-kill-bacteria-and-germs/ https://dailyhomesafety.com/does-dryer-kill-bacteria-and-ger... https://heatkills.org/how-hot/ https://heatkills.org/how-hot/ https://www.quora.com/What-temperature-ballpark-does-the-heated-dry-function-of-a-dishwasher-operate-at https://www.quora.com/What-temperature-ballpark-does-the-hea...
- Wowfunhappy 6y agoQuestion is whether the oven / dryer / dishwasher damages the mask's filter.
- avivo 6y agoDon't just look at single studies. This is a meta-review resource: https://www.n95decon.org/implementation https://www.n95decon.org/implementation It's a collaboration among the many people doing research on decontamination that also takes into account the tacit implementation knowledge of those who conducted the studies.
- everybodyknows 6y agoThanks -- within that review we have this link: https://www.n95decon.org/files/heat-humidity-technical-report https://www.n95decon.org/files/heat-humidity-technical-repor... There's a table of mask damage as a function of high temperature exposure time. All tests were well below the 100C cited by OP.
- romseb 6y agoAnother way to clean masks is to put them in a bowl of hot water (at least 70°C) and add detergent. Let it sit for a few minutes and you‘re good to go.
- snissn 6y agothis will damage n95 masks
- kevin_thibedeau 6y agoMany N95s are rated for a month (20 days) of 8 hours use. If you're only using them for a few hours a day you can stretch their life by quite a bit.
- iscrewyou 6y agoI’ve been using one for a while. I put it on for 30 minutes or so for only grocery shopping. Then stick it in a paper bag and don’t touch it for 7 days. Repeat.
- akiselev 6y agoThat's what I've been doing with a pack of N100s and it works fine. The problem is threefold: leaving it in a car out in the sun will quickly melt the glue holding the plastic filter to the mask, after a few uses it just quickly gets contaminated on the inside unless you're obsessive about decontamination before taking the mask off each time, and that month rating is because the plastic fibers used to make the electrostatic filter dry out and crumble, which can also be pretty bad for your lungs.
- bitL 6y agoWhy don't you cycle 3-4 of them, wearing a different one each day? Viruses won't survive for longer than 3 days inside, so cycling multiple masks would solve the possible contamination issue.
- 6y ago
- yingw787 6y agoI've heard you can use 151-proof grain alcohol in lieu of rubbing alcohol (which has disappeared entirely from store shelves for months) in order to sanitize things. Apparently if you mix it with vegetable glycerin you can create your own ersatz hand sanitizer? I was thinking you could create your own rubbing alcohol by mixing water, sugar, and yeast, distill it over your stove, and then combine it with aloe vera to create hand sanitizer, but that's probably less preferable than using store-bought ingredients that are more consistent.
- buildbot 6y agoI’m not a medical professional, but since 151 is basically 75% ethanol, and ethanol is sold as a cleaner/disinfectant when pure, i assume it would work well.
- akiselev 6y agoPlease don't disinfect an N95 or N100 mask with alcohol (of any sort). It will dissolve the plastic fibers of the filter.
- wrycoder 6y agoHow do you know this?
- klyrs 6y agohttps://smartairfilters.com/en/blog/sanitizing-masks-with-alcohol-degrades/ https://smartairfilters.com/en/blog/sanitizing-masks-with-al...
- wrycoder 6y agoThanks very much for that link (and the links contained in it.) I'm using 75% ethanol in a spray to "sterilize" (for SARS2 only, it's a fragile virus). Even if the efficiency drops after spraying (which is not the same as soaking), I think it's still better than just a cloth or surgical mask. The link to making high efficiency masks https://groups.oist.jp/nnp/diy-face-mask https://groups.oist.jp/nnp/diy-face-mask in the link you provided is quite interesting. The concept of HV electrostatic blowing of polyethylene is new to me - I wondered how N95 masks were made. I note that in the cotton candy machine experiments they reduced the voltage to 50V, lol. I'm going to reserve judgement on the physics behind making electrostatically charged fibers and the question of how long they retain the charge. That's an interesting area to investigate! For example: https://www.tandfonline.com/doi/abs/10.1080/00022470.1974.10470030 https://www.tandfonline.com/doi/abs/10.1080/00022470.1974.10... Ethanol and isopropyl alcohol don't dissolve polypropylene, so the efficiency loss must be due to some other effect. If the small fibers in the N95 mask have charge embedded in manufacturing, i.e. they are electrets, perhaps the removal of surface charge by alcohol (or screening by adsorbed alcohol?) is only temporary, and if the masks were tested a couple of days later, perhaps their efficiency might have recovered? https://search.proquest.com/docview/236317922 https://search.proquest.com/docview/236317922 I would appreciate it if the Federal administration put some effort into upping production of N95 masks for everyone - I've used them for years as dust masks, and now they are not readily obtainable. I still have a small stash, which we reuse and spray down with Everclear 151 after use.
- petra 6y agoGenerally,the instant pot requires at least 1 cup of water when running, according to the manual. How does this work without water ?
- lightlyused 6y agoYou can put another container inside the instant pot to hold the masks. That is how you make things like cheese cake in them.
- petra 6y agoBut steam may ruin the masks, and the instructions on sanitizing don't mention water.
- masklinn 6y agoI'm also wondering, IIRC rice cookers rely on the temperature of the pot not exceeding 100C until all the water has evaporated (which is why getting the correct rice/water amount is important). Without any water in the container I would expect the pot to quickly exceed 100C and shut off. Mine certainly seems to provide no way to maintain such a temperature, I'd guess it'd just switch to "keep warm" and AFAIK that's nowhere near 100C (maybe 60~70).
- weaksauce 6y agothe cheap rice cookers use a temperature switch that triggers after it reaches a bit over 100C yes.
- jefftk 6y agoHow does this compare to just letting the mask sit for several days?
- Falloodude 6y agoCooking the mask ensures that microorganisms on it will die and not pose a risk to the wearer. A mask sitting around for several days can still harbor them in some cases.
- jefftk 6y agoI see that in general, but if we're wearing N95s specifically to protect against the coronavirus then several days seems like it should be (a) enough and (b) not as hard on the mask?
- NeutronStar 6y agoSure for CVOID, but then you'd be exposing yourself to other microorganism that would probably not become a pandemic but still hurt you a little bit.
- coding123 6y agoThis is what I do. I just place it in a plastic bag and don't use it for about a week. I have enough to let me use one each day and quarantine the used mask for a week.
- mypalmike 6y agoWhat's the plastic bag for? Seems like a good way to promote bacterial and fungal growth.
- distances 6y agoI'm using open plastic bags for avoiding touching the mask itself. I figure there's enough air circulation when I let the bag sit open on a shelf. Granted a paper bag could be better.
- RobLach 6y agoWouldn’t that jeopardize the filtration ability of these masks by affecting the fields of the electrets under heat?
- weaksauce 6y agoabsolutely. don't do this please. The filter is able to filter out particles smaller than 0.3um by using weak electrostatic forces. baking it will make the mask less effective. if you can just have a few masks that you rotate through... the best would be a 3 day rotation. there's a good reason the CDC doesn't say to do this. anyway .3 micron particles are the hardest for a mask to filter out because they are small and tend to go in a straight line more than the smaller particles. the filtration effectiveness of the mask is a u shaped curve with a trough in the region of the .3 micron particle sizes.
- clairity 6y agoif your concern is corona, there's no need to do any of this for most people, most of the time (i.e., not a front-line worker). the likelihood of getting live corona on the mask is pretty low, and any corona that does get on the mask will die naturally overnight. certain situations like going to a party might warrant it, but in that case, just throw the mask away and use a new one next time. if you're more worried about other bacteria and viruses, it's a little more relevant, but not much for most of us. despite the endless news coverage, it's just not worth worrying about unless you're often in elevated risk situations, like being a medical worker. just wash your hands occasionally (particularly after situations like going to the bathroom or handling raw meat).
- gfodor 6y agoYou make a lot of claims here about how to properly protect oneself, and as matters as important as this one, citations should be considered strictly necessary.
- BoiledCabbage 6y agoAnd the reasons people ask for citations is what you are saying is very misleading. The CDC estimates that 45% of US Adults fall into these increased risk categories. So no, it's not just people fighting off cancer it's almost half the country. > We estimated that 45.4% of US adults are at increased risk for complications from coronavirus disease because of cardiovascular disease, diabetes, respiratory disease, hypertension, or cancer. Rates increased by age, from 19.8% for persons 18–29 years of age to 80.7% for persons >80 years of age, and varied by state, race/ethnicity, health insurance status, and employment. 1. https://wwwnc.cdc.gov/eid/article/26/8/20-0679_article https://wwwnc.cdc.gov/eid/article/26/8/20-0679_article
- andai 6y agoAm I reading this right, does this mean that 45% of the country has a serious pre-existing medical condition?
- erichurkman 6y ago
- pydry 6y agoI bought one of these UV sanitizer boxes to sanitize my N95s: https://www.amazon.co.uk/gp/product/B085XZPLVS/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 https://www.amazon.co.uk/gp/product/B085XZPLVS/ref=ppx_yo_dt... I'm still not totally certain how well it really works, but I know it works better than those UV wands (you need at least a few minutes of exposure). It's also neat for a few other things that it's probably healthy to sterilize a bit more frequently (e.g. keys, phone, toothbrush heads).
- hbcondo714 6y agoYup, my wife went all out and got one of those UV sanitizer boxes[1] too along with the Under Armour face masks[2]. Their instructions say to wash it but it's convenient to just place in a box. We have also been cleaning other items in there including baby toys. [1] https://lumolite.com/ https://lumolite.com/ [2] https://www.underarmour.com/en-us/p/ua-sportsmask/1368010.html https://www.underarmour.com/en-us/p/ua-sportsmask/1368010.ht...
- everybodyknows 6y agoUnderarmour.com: > Polyurethane open-cell foam lets air through ... And virus particles.
- Johnny555 6y agoI can understand how UV light can sterilize hard surfaces like a cell phone, but how does it sterilize multi-layer fabrics where the virus may be shaded from the UV light by the fabric?
- hbcondo714 6y agoTheir website states and shows that face masks are items you can sanitize. They also have a testimonial from a health care worker that uses it for masks. Neither go into details but their FAQ page says "UV-C light only sanitizates surfaces it can reach" so that is a fair question you are asking they should address.
- 6y ago
- everybodyknows 6y agoSARS Cov-2 infectiousness decays exponentially, with the time constant a function of temperature and humidity. A two-parameter calculator: https://www.dhs.gov/science-and-technology/sars-calculator https://www.dhs.gov/science-and-technology/sars-calculator
- jdc 6y agoSounds like wetting the towel first would be the way to go.
- afterburner 6y agoCooking a wet towel would turn the water to steam, I'm guessing that would be problematic for the mask's durability. Also, the humidity factor seems counter intuitive to me on that site. I thought the virus survived longer in the air in damp spaces, while sunlight dried out the virus rendering it inert.
- distances 6y agoWould it be wrong to infer from this that letting a face mask sit in room temperature for a week is almost guaranteed to make it safe for use again?
- radus 6y agoNot wrong at all. I do 3 days in paper bags. Reasoning for paper is that it breathes more than plastic and the half life of the virus is shorter on paper as well.
- Abishek_Muthian 6y agoI wonder whether the results change with the pressure cooker. I had ilizarov apparatus[1] on my legs for over a year(once during age 7 and another during age 15) and my mom used to sterilise the instruments (Scissors, Forceps) used for dressing wounds at home(every alternate day) in pressure cooker(on advice of the doctor). I presume, pressure cookers are still being used for the sterilisation of instruments[2] in several parts of the world as its still common than an electric cooker. [1]https://en.wikipedia.org/wiki/Ilizarov_apparatus https://en.wikipedia.org/wiki/Ilizarov_apparatus [2]https://cdn.ymaws.com/sites/adint.site-ym.com/resource/resmgr/NewsArticles/Use_of_pressure_cookers_for_.pdf https://cdn.ymaws.com/sites/adint.site-ym.com/resource/resmg...
- necovek 6y agoI am sure they perform sterilization effectively, but introduction of water/steam (which is under pressure in a "pressure" cooker) will almost certainly deform a mask like an N95 mask.
- Abishek_Muthian 6y agoI thought electric cooker uses less water in contrast to no water.
- everybodyknows 6y agoDo not do this. Pressure cookers exist to accelerate cooking, by raising the boiling point of water above 100C, because pressure resists boiling. All plastics in the mask will deteriorate rapidly.
- anotheryou 6y agoI rotate 10 masks, wear each of them 20m/day at most. Drop out of rotation if smelly (only happened once with serious sweating).
- ConcernedCoder 6y agodirect sunlight kills everything eventually
- cf100clunk 6y agoAn autoclave is what the electrical cooker is being used to emulate. A pressure cooker is a better option if you'll be on the road, camping, or otherwise without electricity. Researchers in Canada already proved several months ago that N95 masks could be sanitized this way: https://news.ycombinator.com/item?id=22761264 https://news.ycombinator.com/item?id=22761264
- westurner 6y agoUnfortunately the referenced NewsArticle does not link to the ScholarlyArticle https://schema.org/ScholarlyArticle https://schema.org/ScholarlyArticle : "N95 Mask Decontamination using Standard Hospital Sterilization Technologies" (2020-04) https://www.medrxiv.org/content/10.1101/2020.04.05.20049346v2 https://www.medrxiv.org/content/10.1101/2020.04.05.20049346v... : > We sought to test the ability of 4 different decontamination methods including autoclave treatment, ethylene oxide gassing, ionized hydrogen peroxide fogging and vaporized hydrogen peroxide exposure to decontaminate 4 different N95 masks of experimental contamination with SARS-CoV-2 or vesicular stomatitis virus as a surrogate. In addition, we sought to determine whether masks would tolerate repeated cycles of decontamination while maintaining structural and functional integrity. We found that one cycle of treatment with all modalities was effective in decontamination and was associated with no structural or functional deterioration. Vaporized hydrogen peroxide treatment was tolerated to at least 5 cycles by masks. Most notably, standard autoclave treatment was associated with no loss of structural or functional integrity to a minimum of 10 cycles for the 3 pleated mask models. The molded N95 mask however tolerated only 1 cycle. This last finding may be of particular use to institutions globally due to the virtually universal accessibility of autoclaves in health care settings. The ScholarlyArticle referenced by and linked to by the OP NewsArticle is "Dry Heat as a Decontamination Method for N95 Respirator Reuse" (2020-07) https://pubs.acs.org/doi/full/10.1021/acs.estlett.0c00534 https://pubs.acs.org/doi/full/10.1021/acs.estlett.0c00534 . Said article does not reference "N95 Mask Decontamination using Standard Hospital Sterilization Technologies" DOI: 10.1101/2020.04.05.20049346v2 . We would do well to record that (article A, seemsToConfirm, Article B) as third-party linked data (only if both articles do specifically test the efficacy of the given sterilization method with the COVID-19 coronavirus)
- Jerry2 6y agoMy family has been decontaminating our N95 masks with ozone. I bought a battery-operated O3 generator and if you place it into a tupperware container along with the mask, it will decontaminate it and then you can use it the next day. Yale School of Medicine has done a study on the efficacy of this method. [1] I prefer this method because it doesn't degrade the mask at all, it needs no disinfecting/harsh chemicals, it penetrates into the pores of the mask completely, and it's near fool-proof. [1] https://www.medrxiv.org/content/10.1101/2020.05.28.20097402v1 https://www.medrxiv.org/content/10.1101/2020.05.28.20097402v...
- rayuela 6y agoWow this is actually incredible if this works. However this study was tested bacteria and relate it to covid in the following way: "an ozone application achieves a high level of disinfection against PsA, a vegetative bacteria that the CDC identifies as more difficult to kill than medium sized viruses such as SARS-CoV-2 (Covid-19)" Would the implication be that this same method works on covid as well? That is not immediately apparent to me...
- solinent 6y agoIt sounds like it's saying "ozone kills the tougher bacteria than Covid at a very high rate". So directly it says absolutely nothing about Covid but implicitly it does seem to state that it should also kill Covid since it's less tough to kill than the vegetative bacteria. I guess they can't make that statement directly--there's no evidence related to Covid here. I'd ignore it.
- im3w1l 6y agoBut why are they making this proxy argument, why not test with covid directly? Makes me think they did test with covid and it wasn't working.
- solinent 6y agoMaybe the mechanism of death is similar so if it kills a more difficult strain the same mechanism will kill the "easier strain". It doesn't directly state it though, I think it's just speculation. It doesn't belong in a science paper except maybe in a speculative section about the future I guess.
- foobiekr 6y agoRelated: can anyone explain why there are still no n95 masks available? It seems like, a few months in, it's surprising that there are none available for non-medical buyers. Is this perception wrong?
- Larrikin 6y agoThere is no unified approach to the virus and states and are fighting each other for the little supply there is
- tarikjn 6y agoI think price-gouging laws could also have something to do with this. Suppliers have increased their prices in what is essentially protracted inflation from demand. But in most states retailers are not legally allowed to increase price tags which was triggered in March when most states entered a state of emergency/declared disaster [1]. So the results is that retailers have to stop stocking these or they lose money; and the increased demand doesn't fully reach suppliers which means that in turn, manufacturers have also less incentives to increase production. [1] https://www.natlawreview.com/article/price-gouging-laws-and-overlapping-states-emergency https://www.natlawreview.com/article/price-gouging-laws-and-...
- mistrial9 6y agoPlease clarify ".. So the results is that retailers have to stop stocking these or they lose money .. "
- tarikjn 6y agoCiting from https://www.patriotsoftware.com/blog/accounting/price-gouging-laws-by-state/ https://www.patriotsoftware.com/blog/accounting/price-gougin... > New York's Consumer Protection Law prohibits price gouging during an emergency: What is considered price gouging: 10% or more price increase. When price gouging laws apply: During an emergency. Products or services the law applies to: Necessities. Say your gross margins on said masks were 50%, you paid $1 per mask and sold them $1.50 plus tax. Now the same branded masks are $2-3 from the supplier and you cannot legally sell them without losing money.
- swayvil 6y agoI place mine in a silver chalice and chant "Fauci" and "Gates" over them for 20 minutes. Not sick yet.
- argonaut 6y agoNone of this is necessary for non-healthcare workers, since the virus will die off on a fabric mask in a few hours. 1) Not a single study has demonstrated that viable Sars-Cov-2 virus survives on porous materials in the real world 2) Even before Covid, it was known for decades (common medical knowledge) that human coronaviruses and flu viruses do not remain viable on porous materials for more than several hours. That this common knowledge is not so common knowledge among the public is a failure of public health communication. The one or two alarmist studies showing that the virus "survives" X number of days don't reflect the real world because 1) the researchers literally directly douse or soak the surface with a huge viral load, and 2) the researchers usually only look for viral genetic material, not whether the virus can infect cells. Viability != detecting viral genetic material (same story for people - we shed viral genetic material long after we stop being contagious). There is a reason the CDC has always said surface transmission is rare: https://www.nytimes.com/2020/05/22/health/cdc-coronavirus-touching-surfaces.html; https://www.nytimes.com/2020/05/22/health/cdc-coronavirus-to... there have been no documented cases of surface transmission: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cleaning-disinfection.html https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si... Fortunately some in the media are catching on to the hygiene (security) theater: https://www.theatlantic.com/ideas/archive/2020/07/scourge-hygiene-theater/614599/ https://www.theatlantic.com/ideas/archive/2020/07/scourge-hy... Citations for 1) and 2): Most studies use unrealistic starting doses: https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(20)30561-2.pdf https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099... Other human coronaviruses don't survive long on porous surfaces (gone by 6 hours): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7134510/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7134510/. A hospital randomly collected patient and real surface swabs (including non-porous surfaces) for original SARS, a minority were PCR positive, none of the swabs were infectious (viral culture): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7134510/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7134510/. Same story for flu (virus can be detected for days, but inactive and not viable after a few hours): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222642/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222642/. I could only find this study on Sars-Cov-2 that cultured the virus (still used a huge viral dose in a lab setting, not the real world). Even though they were able to culture the virus, only 1% of virus remains after 6 hours on a surgical mask, several orders of magnitude less for cotton clothing: https://www.medrxiv.org/content/10.1101/2020.05.07.20094805v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.05.07.20094805v... This long post was originally meant to be a reply to someone asking for a citation; it's yet another example of how much effort is required to combat misinformation.
- averros 6y agoThe N95 masks are very good at collecting and retaining dust - both organic and inorganic. Organic debris in warm humid environment created by breathing is an ideal breeding ground for bacteria and fungi. Which can easily cause much more serious illness than COVID. Heating and using any other methods of decontamination do not remove the debris from the filter. The masks have to be discarded after a couple hours of use, period.
- matt-attack 6y agoCan someone explain why you can’t just have three masks, and circulate through them? We’ve been told that the virus dies after 3 days just sitting there. Why do I need to decontaminate it ad in TFA? I don’t get it.
- Xcelerate 6y agoI have a set of N99 masks that I just rotate over a period of about a week in brown paper bags. If you don’t have enough masks for that, I imagine a sous vide machine (like the Joule) would work. Just seal the mask in a plastic bag and place under water for the appropriate amount of time. These things hold very precise temperatures.
- mariushn 6y ago> I just rotate over a period of about a week in brown paper bags. Why the brown paper bags? Do these ensure better evaporation? Wouldn't simply keeping the mask somewhere kill the virus in 3-4 days? Or, what would be the best way to ensure this within 3-4 days without any damage to the mask?
- aaron-santos 6y agoHappened to have bought a towel warmer with UV sanitation pre-pandemic. There are some early reports that heat and UV neutralize the virus.
- exabrial 6y agoMy big concern is modifying the electrostatic properties of the fibers which is how much larger fibers stop much smaller particles (order of 10x-100x). It looks like moderate heat and no humidity in this study didn't have those effects. Hoping this can be peer reviewed soon!
- jaclaz 6y agoI don't want to appear a naysayer, but everyone should be aware that N95 masks usually aren't effective at the intended level because of the lack of a fit test and training by the non-professional users. See: https://news.ycombinator.com/item?id=23957506 https://news.ycombinator.com/item?id=23957506
- ablekh 6y agoI would not use this method for N95 masks with plastic exhalation valves due to potential melting of the latter.