Believe it or not, that kitchen sponge is the dirtiest item in your house. Luckily, there's an easy way to clean it. It soaks up all sorts of germs that live there happily, as the sponge usually remains slightly damp by the sink — a perfect home for those nasty microorganisms. Take that sponge to the microwave to kill them.
How to Sanitize a Sponge Using the Microwave
Place your wet or damp kitchen sponge in the microwave and heat it for one minute. Be sure that the sponge is wet when microwaving it, as heating it when dry can be a fire hazard. The heat will dry out the sponge and kill 99 percent of lingering bacteria in its nooks and crannies.