We've already faced two years of covid-19 pandemic, and if there's one subject we apparently understand well about, it's the masks. In early 2020, tissue masks were declared by health agencies as the easiest and most effective prevention against coronavirus —apart from isolation. But as research progresses, it turned out that they're not as secure as some disposable options —in some cases, they could filter only 5% of aerosols from sneezing.

Researchers advise that the best masks to ensure protection are those of model PFF2 and N95: both ensure the filtration of up to 95% of the particles suspended in the air, in addition to sealing the mouth and nose very well. So, if these masks are more efficient, what to do with that large amount of cloth models that were purchased or sewn at the beginning of the covid-19 pandemic?

Many people who care about the environment have wondered what would be the best destination of these masks, since the amount of fabric used in them is large. It is estimated that, only in 2020, the residents of the city of São Paulo (SP) have used so many meters of fabric that it would be possible to cover 68 soccer fields.

A plausible solution is recycling, but there is an important issue here: tissues do not contain just one type of fiber. There are masks made of natural fibers such as cotton and linen, and other synthetic fibers such as polyester and nylon.

Therefore, recycling a fabric is not as simple as recycling glass or metal. In theory, it is easy to reuse a cotton or polyester mask, but you run into a problem, which is the lack of structure to do this. "There are no real mechanisms on where to take these masks. You can't just take them to a collection point or put them in dumpsters, like you do with Coke bottles," explains Robert Speight, professor of Microbial Biotechnology at the Queensland University of Technology (Australia).

So, what's the solution?

The ideal solution for old fabric shades would be to find an appropriate disposal site of this material. In São Paulo, Renovar Têxtil collects textile waste in the Region of Brás and Bom Retiro and receives masks that will be used for defibering, a process that causes the fiber to be reused.

However, not all cities have these centers available —and one destination given to these masks is incineration, which generates polluting effects on the atmosphere. In that sense, maybe throwing them in the trash is even better than burn them.

Another idea is to reuse the fabric of the masks, using them, for example, to make quilts, cleaning cloths, fuxicos or new clothes, depending on creativity. If you decide to give new life to the masks, don't forget that they need to be well sanitized. An easy and safe method to do this is to dip them in a solution of 1 liter of water and 10 milliliters of bleach for 40 minutes.