A new study out of Northwestern found that we can make our cloth masks way more effective if we simply add an outer layer of nylon pantyhose to them. The nylon is not just highly effective for filtering, it also creates a snugger fit to the face that reduces how much air can get through, which can boost the performance by 50%.
According to Loretta Fernandez, an assistant professor of civil and environmental engineering at Northeastern University, "It really improved the performance of all of the masks, and it brought several of them up and over the baseline mask we were using, which was a 3M surgical-type mask.
All you have to do is cut an old pair of pantyhose and wear it over your mask. Fernandez recommends using a queen-sized pair to make breathing easier. Not only is it washable, but it’s something we all have lying around. (Glamour)