Reusing PPE and time based 'disinfection'

I’ve been told that COVID can ‘remain’ on surfaces for a certain period of time dependent on the surface. Copper 4 hours, Cardboard 24 hours, Stainless Steel 3 days, whatever.

If I have PPE items such as a mask or rubber gloves (or grocery items like a box of cereal), can I simply leave them to sit somewhere for 3 days and assume they are no longer infectious? Should I wash them in soap and water as well (the PPE, not the cereal)?

I appreciate that we’re not supposed to reuse PPE, but if I throw away what I have after each use, it won’t last very long at all.

The ‘remain’ time is actually how long there are detectable quantities of the virus on the surface. However, that doesn’t mean that they are still a serious threat for contagion, particularly if you otherwise practice good hygiene (don’t touch your face or habitually like doorknobs). Really you should treat thos as guidance for what surfaces need thorough and regular cleaning rather than a countdown clock.

As far as PPE reuse, although it may be unavoidable there is still significant concern, both with contamination and degradation with use. The N95 respirator masks, for instance, become less effective as the filter material is moistened with breath as the user wears them. Allowing them to dry or gently heating them helps to desiccate any virions that are on them but heat also causes the non-woven substrate to clump and lose the electrostatic properties that causes particles to stick to it. If you are going to reuse PPE like masks, the best thing you can do is dry them thoroughly and put them in direct sunlight for at least a couple of hours (or under intense UV-C for several minutes).


Dr. John Campbell on Infection and Symptoms, cued up to his discussion about wearing and handling masks.

I recommend watching the entire video, and indeed, his daily assessment of the COVID-19 pandemic based upon reported data from various countries and informed (and explicitly qualified) speculation as well his repeated reinforcement of why social (physical) distancing is crucial in limiting the effects of the epidemic and the need for mass testing.