It uses a phone charger to generate heat that kills bacteria.

A new self-cleaning face mask has been developed in Israel. The mask plugs into a standard phone charger. A unit inside the mask is then activated that generates heat that will kill most bacteria that might have landed on the mask while wearing it. According to the developers, the entire cleaning cycle takes about 30 minutes.  The developers said that disposal masks are not cost-effective in many poor countries and that they hope that this new reusable mask will give those in need the chance to practice good hygiene, using the latest technology.