Heat in the microwave
No one likes the idea of cleaning dishes with a germy sponge, which is why we all know we should be cleaning ours on the regular.
Slightly dampen your sponge, pop it in the microwave for 90 seconds on full power, and you'll reduce the amount of bacterial contamination on it by up to 99 percent, according to research published in 2006 in the Journal of Environmental Health. Just make sure your sponge doesn't have any metal scrubbers or you'll be adding "buy a new microwave" to your list of things to do.
3 Other Ways to Clean a Sponge
Here are other 3 other methods to sanitize your sponge. They're listed in order from most to least effective, so choose wisely.
Mix 3/4 cup of bleach in one gallon of water and soak the sponge for five minutes, then rinse – and that's it. In testing, the bleach solution killed 99.9% of the three bacteria strains from the test sponges (scrub and regular cellulose), which is the benchmark based on the EPA's requirement for sanitization of non-food-contact surfaces.
The dishwasher also killed 99.9% of germs. To use, add your sponge to a regular dishwasher load, using the "heated dry" setting.
This method eliminated 99.6% of bacteria. All you have to do is soak your sponge in full-strength vinegar for five minutes, then rinse.
But no matter how diligent you are about cleaning, your kitchen sponges won't last forever. Clean them weekly, and toss shabby ones every two to three weeks, depending on use.