Using blue shop towels in homemade face masks can filter particles 2x to 3x better than cotton, 3 clothing designers discover after testing dozens of fabrics Suay Sew Shop Lindsay Medoff, the CEO of Suay Sew Shop, a 30-employee boutique Los Angeles clothing manufacturer, wants the armies of people sewing homemade surgical masks to add a specific blue shop towel inside them. Medoff and two friends were appalled by the dozens of mask patterns calling for cotton, a highly breathable, permeable fabric, and became obsessed with finding a fabric better suited for the job. They built a lab that could test particle filtration down to 0.3 microns and tested every fabric they could find, from coffee filters to industrial materials. They discovered that by adding two blue shop towels and using a design that produces a tighter-fitting mask, they could make a mask that could block up to 95% of the particles they could test, while the cotton masks blocked 20% to 60% of the particles. These are not meant to replace the N95 masks worn by healthcare workers — they're designed to be an alternative to the cotton masks that many people are making and wearing for quick trips to the grocery store. The women are sewing 200,000 masks and giving them — and a design — away, as well as raising money to pay their workers their full wages. They're also raising money to get their mask tested with the actual COVID-19 pathogen to see whether their design could be validated as a safer solution during the mask shortage. (more on the link) .