I did a bit of googleing. And I learned two things. First, there are some everyday products lying around your house that offer excellent filtering capabilities. Second, how the mask fits is equally as important for it to be effective.
So, studies show that a paper towel alone filters out 96% of 1.0 micron sized particles. Compare that to N95 masks that filter out 99%. So, what I’ve done is to take a bandana, which alone only filters out 36%, and I put the paper towel in the open bandana. I then fold the bandana over the towel so there are 3 layers of bandana plus the paper towel. I don’t fold the paper towel so that I get the most coverage from the towel. When I go food shopping I put it on before I get out of the car and tie it behind my head. I tie it nice and tight so there are no gaps and my entire face is covered. It fits better than the surgical mask that I also have. And after I’ve worn it for a bit I just rinse out the bandana, toss the paper towel and replace it with a new one. And I’m not running around looking for a store that has them in stock or trying to find them online. This works for me. Fingers crossed that the studies are correct. I'm sure someone will say that the covid particles are much smaller than 1 micron. That's true. But the covid particles are attached to moisture droplets that we humans emanate that are larger than 1 micron. I would definitely not feel good about using just a bandana as alone they are probably the worst filters. But the paper towel plus 3 layers of bandana I figure gives me as good protection as a surgical mask. Lots of other ways to make a homemade mask. This one requires no sewing or cutting. Just place, fold and tie. Nothing much more simple than that.