Tightly knit cotton material, like a T-shirt. (A scarf can work. The fabric should be big enough to fold several times and cover your nose and mouth.)
Two rubber bands or hair ties
How to Assemble the mask:
A. Cut the bottom 7 to 8 inches off of a T-shirt (cutting horizontally), so that you have a strip of material.
B. Lay the material out flat in front of you, and turn it 90 degrees so that what used to be the bottom hem of the shirt (it's usually double stitched) is facing left or right.
C. Fold it from the bottom to the middle, and from the top to the middle. Repeat this step a second time.
D. Loop a rubber band or hair tie around each end (left and right), leaving a few inches of fabric, so each side looks like a candy wrapper.
E. Fold the excess material over the band, with each side meeting in the middle, adding another layer to the mask.
F. Put a band over each ear, making sure the material fits snugly to your face. The pressure on your face should keep the material and rubber bands in place.