In these times of Coronavirus, quarantine and special care, the use of the mask o tapaboca is necessary, and according to the recommendations of health experts, it must be sufficiently covering and waterproof so that the small drops do not pass through the fabric and expand on the outside.
And in the search for homemade chinstrapsI found this video of Gustamontón that I thought was the most suitable, because it uses a cotton fabric as recommended, is double and in the center has a waterproof fabric that makes it even safer.
Some doctors recommend placing a napkin paper or kitchen roll between the chinstrap fabrics, this would replace the waterproof fabric. This is a good fact, since we cannot go around shops looking for all the necessary elements for the chinstrapping.
Next you will be able to see the video of how to make homemade chinstraps with fabric. It is very well detailed every step, so you will have no problem if you are already familiar with sewing.