What types of home-made masks are best? A video case study published in the journal Thorax, showed that two- and three-layered masks work best. Researchers used an LED lighting system and high-speed camera to film the dispersal of airborne droplets as participants spoke, coughed, and sneezed while wearing different masks. While single-layered cloth coverings reduced droplet spread from talking, double-layered masks better reduced droplet spread from coughing and sneezing.