Any recommendations for suppliers of washable face masks that follow the advice in https://www.sciencenewsforstudents.org/article/science-homem...?
"Overall, a combination of fabrics worked best. And not just any fabrics. The top performers paired 600-thread-count cotton (meaning 600 threads were woven to make up each square inch of fabric) with two layers of either silk or chiffon. On average, each type stopped at least 90 percent of the particles."