As indicated in the package inserts and in the packaging of the KN95 or FFP2 masks, they are not manufactured with the idea of being reused. However, only in case of extreme need, and due to the lack of supplies of these protective masks that still exist in some places due to the incidence of the Covid-19 coronavirus pandemic, there are different options to disinfect and reuse them. Although they make them lose some effectiveness, this loss does not prevent their reuse from being somewhat risky.
Before continuing we must warn that these techniques come from official health sources and that their use is under the responsibility of the user. Obviously, they should not be used in health care settings with a high risk of contamination or when people affected by coronavirus and other contagious respiratory diseases are involved.
There are some previous indications that should be taken into serious consideration: The masks must not be broken or dirty, must maintain their original shape, so that they do not allow undesired lateral filtrations and must be avoided to be cleaned with water or to refuse those that are excessively humid, because they would lose their water-repellent capacity and, therefore, their anti-contagious effectiveness.
Here are some of the methods (we remind you that their use is under the responsibility of those who decide to carry them out and we echo official Spanish health sources):
– Use convection oven in its dry heat mode at 70º for 30 minutes.
– Use MGS microwave for 30 minutes at 65ºC, with humid heat.
– Steam re-styling at 121ºC for 15 minutes
– Using 99% ethanol for one hour and allowing the environment to dry
– Using ozone gas for one minute.
We would like to clarify that these methods guarantee at most reuse for 2-3 uses, since they imply, to a greater or lesser extent, a loss of insulating effectiveness; therefore, they should not be taken as a guarantee of continuous reuse.
We insist that this entry is merely informative and that it is not based on our own research, but rather echoes other research and advice from official medical bodies, as you can consult in more detail and comprehensively at https://www.murciasalud.es/preevid/23560 ( spanish )