What to do: Layer a cloth mask on top of a surgical or medical procedure mask. This helps the entire setup fit more snugly. Make sure the fit is comfortable and doesn’t have gaps around the sides of the face or nose.
What not to do: Do not combine two disposable masks, which are not designed to fit tightly. Wearing more than one disposable mask at a time will not improve fit. Also, do not wear a KN95 mask, a type of filtering face-piece respirator, with any other mask.
Cloth-mask dos: Choose a cloth mask made of multiple layers of tightly woven, breathable fabric that includes a nose wire, which can help improve the mask’s fit. Does the mask block light when you hold it up to a bright light source? Then it’s a good construction.
Cloth mask don’ts: Stay away from cloth masks with exhalation valves or vents, which can allow respiratory droplets to leak into or out of a mask.