I used quilting cotton fabric. I have tons and this seems like a great time to use this fabric that has just been sitting around not being used. I feel like doing this is helpful and I really believe that having an activity to do like these easy masks is helping my mental health while I Stay At Home during this crisis.
You will wash the fabric before you begin and after you are done. And I chose not to use dryer sheets when I put it in the dryer. I felt it might be healthier not to have that residue on fabric that you breathe through on your face.