Step 3: “Good” if the layer has “melted” and come apart instead of catching fire
The Flame Test
The middle layer comprises of hydrophilic elements that is not made of paper, but a “melt-like” non-woven fabric material that helps to filter out the dust, germs and bacteria. This layer is critical in protecting against unwanted transmission of particles to and from you, and the effectiveness can be determined with the flame test
Cut the mask open to deconstruct it, removing the middle layer of fabric. With a match or a lighter, safely set fire to the fabric. The fabric should melt and slowly disintegrate, and if it catches fire and burns, it could be an indication of poor fabric quality.