If you hold a dish towel/tea towel up to the light or a well lit window and you can see thru it, those holes in the weave are grand canyon sized openings for a 0.01 virus. If you’re going home-made, you’ll need a nonwoven material like felt with lots of nooks and crannies to trap the particles. Like the filter on a air purifier or fish tank for instance where the static charge of the poly material acts like a magnet.
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