Cheryl F.
I don't know how "scientifically effective" these filters are but I can say that I took a standard pipe-cleaner, folded it into thirds, wound it together, and sewed it into the top of the mask so I could get a tight fit at the nose (like my n95 mask). And when I wore my mask today I could feel resistance when I was breathing in while talking so there's definitely some barrier protection!


























