I recently ordered a bag of those stretchy cotton loops that kids use on a loom to make pot holders -- know what I mean? I cut about 1" off each one, and it makes a really soft over-the-ear wrap instead of using elastic. This can be for a pleated mask where you sew the elastic inside and then turn, or a 'shell' mask that is sewn top and bottom, turned, and then the ends sewn closed. I have long ago forgotten the names of any patterns!