Ear loop masks are common but unfortunately are often uncomfortable and do not provide a good seal around the face. Head-strap masks are more effective, but harder to find and more expensive. Turn an ear loop mask into a head strap mask using this simple trick.
What you need: 1 mask + around 2 feet of thin, sturdy cord, yarn, or thread.
Step 1
Cut the ear loops of the mask in the middle of the loop.
Step 2
Tie a simple overhand knot on each of the four ends of the mask.
Step 3
Cut the string into two segments of approximately 1 foot (30 cm)
Step 4
Tie a loop knot at ONE end of each piece of string. This will be used to keep it from sliding out.
Step 5
Pick a side for the fixed string (left or right). On that side, tie a square knot connecting one of the mask straps and the untied end of one string. Repeat for the other mask strap and other string on that side.
Step 6
Loop around once 
Mask strap over string 
Tuck mask strap through loop 
Completed knot, loose 
Completed knot, pulled tight. The white mask strap can slide left/right along the blue string only when held like a zipper and slid.
Tie a two half-hitch knot˺ on the other side (right or left) between the mask strap and the corresponding string. This allows mask strap to slide along the string when you pinch over the knot and slide, similar to using a zipper pull, but it will not slip when in use. Repeat for the second string and remaining mask strap.
Congratulations! You now have a head strap mask.
