Wrap this around your mouth.

Cabin fever driving the urge to shout a martial artist's name at front-liners? Running out of masks because somebody bought the entire supply and mailed it home (which is an action I associate more with a criminal than a scapegoat)? Why not try this instead?
I found a simple pattern for masks and modified it, using available supplies to fashion the straps. The original version used elastic hair ties to hold the mask to the wearer's face, and two rectangles of fabric whose sizes varied depending on the size of the head. I used material measuring 11 in. by 5 in. (27.94 by 12.70 cm - there, happy, metric users? Yeesh.) for each mask, and made three variations using shoelaces and two types of hair ties for the straps. The original pattern's recommendation of double stitching over the attachment points is a worthwhile one to follow.
Sewing machines make the process a lot faster, thank goodness, and clothes irons make for tidier hemlines. The sewing machines I've seen have a gauge on the needle plate (immediately beneath the needle on the base of the machine) that shows how far the edge of the fabric is from the foot (the part near the needle that holds the fabric down). Of the feet that came with the machine, I used the widest for this project, and used the edge of the foot itself to determine the width of the hem.
I was lucky enough to have two sorts of fabric left over from another project - one satin, one muslin - to make these. Two layers offer more protection while still being thin enough to breathe comfortably, though I think other versions suggest a third layer.*** The muslin's a bit more comfortable against the face, and I'm counting on the smooth surface of the satin being easier to wipe off. I got enough 11-by-5 pieces of both to make six masks.
It doesn't matter as much which side of the muslin faces outward, but for this project, the smoothest surface of the satin has to face inward. Sew the long edges of the fabric first, as close to the edge as possible, then turn the whole tube inside out. Iron the hem flat. Afterwards, tuck the ends of the tube inward, then position the ties into the corners before sewing the sides shut.
The top mask is the one that follows the original pattern most closely, with the hair ties used to hook onto the wearer's ears. I stretched the tie before sewing it into the hem, which is the most difficult part to manage, but was helpful in the end result. The fabric bunches up around the tie's relaxed form, which I found helpful when testing it on my own face - it causes the mask to curve more snugly around cheeks and chin. (Snuggly is for quilts.) However, the thickness of the tie (which I appreciate when I have it in my hair) is a problem when hooking it over the ears, especially if one wears glasses. I'll use the thinner tie next round.
The second uses a thinner hair tie from the same maker. This line of products uses no metal to form the loop, which makes the tie a bit easier to snap at the adhesive joining the ends (They're plenty sturdy enough for my needs, though - the pack I'm on has lasted years.) Instead of looping over the ears, the ties stretch across the back of the head. The mask doesn't follow the lines of the face as closely as the first, but I think the ties hold more securely. For the next round of this, I'll attach the ends of the ties to the corners of the fabric at a diagonal rather than straight across.
The third uses a single 43-inch shoelace cut into quarters (clear nail polish helps keep the cut ends from fraying) and sewn into each corner. This mask is the one that followed the lines of the face least closely, but I think it's more adaptable for different head sizes. It is, however, a woven rather than a leather shoelace, and wider than the other ties, which means it'll absorb more of whatever it's exposed to. This mask is also the one that takes the most time and effort to put on, and (depending on the person) might require another pair of hands, which is a problem if a front-liner's using this at work. (According to my guinea pig, there's a specific way to tie these in order to make sure the mask stays on. And no diet soda, thanks.)
Samosa.
***Also from my guinea pig - tucking a coffee filter into the space between the fabrics provides a third, absorbent layer that can be discarded. Thing is, leaving one narrow end open would require a different sequence when it comes to sewing, and I'm out of fabric. (Drat.) From my estimation, it would be the same method one uses to make a pillowcase.