The microwave is no place for face masks.

New Hampshire fire officials are warning residents against sterilizing their face masks in the microwave, saying it could easily spark a fire.

“The NH State Fire Marshal’s Office (NHFMO) would like to remind everyone that ‘microwaving their masks to kill germs’ is a fire hazard and an extremely bad idea,” the office said in a Facebook post accompanying pictures of extremely charred masks.

“Cloth masks can overheat quickly and catch fire. Disposable masks also have a metal nose wire and can cause sparks, a fire, and/or break your microwave,” the post continued.

Some states, including New York, have required residents to cover their face should they venture outside, with some businesses refusing entrance to those violating the order.

The Centers for Disease Control and Prevention recommends that cloth masks should be “washed routinely” in a washing machine, while the New York State Department of Health advises masks should “be changed frequently and laundered when they are soiled or wet.”