Placebo masks.
But there is apparently an effect as they tend to keep people apart and less handsey with each other.
Don't think it would be effective in keeping Creepy Joe away though...
Placebo masks.
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Don’t waste your time chasing cheap masks. The only benefit a mask will provide is to keep you from putting your fingers into your mouth and nose. You still have two other entry points on the face, eyes and ears. Best approach keep your fingers off you face, wash your hands with soap and water frequently, and your face at least twice a day.
I have masks good enough to scrape lead paint