toss that sponge

Stop. Drop the sponge and step away from the microwave.

That squishy cleaning apparatus is a microscopic universe, teeming with countless bacteria. Some people may think that microwaving a sponge kills its tiny residents, but they are only partly right. It may nuke the weak ones, but the strongest, smelliest and potentially pathogenic bacteria will survive.

Then, they will reproduce and occupy the vacant real estate of the dead. And your sponge will just be stinkier and nastier and you may come to regret having not just tossed it, suggests a study published last month in Scientific Reports.

The thrifty among us may try to clean a sponge that starts to stink, but it’s probably time to let it go. Disinfecting it, as many have tried, does not necessarily work. You can microwave a sponge, throw it in the laundry or dishwasher, douse it in vinegar or other cleansing solutions or even cook it in a pot. But the researchers discovered more of the potentially pathogenic bacteria, like Moraxella osloensis, on the sponges collected from people who said they routinely disinfected them.

“When people at home try to clean their sponges, they make it worse,” Dr. Egert said — similar to how people can encourage antibiotic resistant bacteria if they don’t follow the doctor’s orders. He says if you can’t clean it perfectly, it may be best to replace it with a new one every week or so — especially “if it starts to move.”