How to clean a cloth mask
A standard laundry cycle is enough to wash the coronavirus off cloth, according to the WHO and CDC.
“Because it’s an enveloped virus, it’s really susceptible to detergents,” says Rachel Graham, a virologist at the University of North Carolina at Chapel Hill. The envelope that encapsulates viruses like influenza and SARS-CoV-2 is a delicate layer of oily lipids and proteins, held together by surface tension.
Laundry detergents and soaps contain surfactants, chemicals that easily break that envelope apart by reducing surface tension, explains Joshua Santarpia, a pathologist at the University of Nebraska Medical Center in Omaha. A surfactant molecule has one end that’s attracted to oil and grease, while the other is attracted to water. The oil-loving end wedges into the coronavirus’s envelope, busting it apart. The remnants get trapped in circular pods of surfactant called micelles and are washed away in water.
“The interaction of that surfactant with the viral envelope pretty quickly destroys the ability of that virus to be infective,” Santarpia says. Potent surfactants are found in most home and commercial cleaning products.
The water temperature in the washing machine doesn’t matter as long as you use detergent. “The masks made of cotton withstand higher temperatures, so if it makes you feel better to wash it at a higher temp, go ahead and do that,” Graham says. The high, concentrated heat from a dryer offers added protection: it’s enough to kill most microorganisms.