How to Clean Your Kitchen Sponge (and When It’s Time to Toss It)

A dirty sponge is one of the germiest things in your kitchen. According to a representative from Clorox, "kitchen sponges can harbor significantly more bacteria than a toilet seat."

Whether it’s scrubbing dirty dishes or wiping counters, you can count on a kitchen sponge picking up and breeding its own stash of bacteria along the way. 

Not every type of sponge or cloth can be cleaned the same way, but we're here to outline some of the best methods. Just keep this in mind: Sometimes an old sponge is a lost cause.

Why Kitchen Sponges Get So Gross So Fast

• Sponges are warm, wet, and full of food particles. If you're not using a sink caddy with good air circulation, your sponges and cloths will harbor moisture. Moisture = faster mold growth.
• Food particles and liquids can't always be disinfected. Using sponges to clean up after handling raw meat is especially risky. If your sponge touches juice from raw chicken or beef, it’s better to toss it. There’s no reliable way to fully disinfect a sponge that’s soaked up juices from meats. It’s not just about removing visible dirt at that point—it’s about getting rid of dangerous bacteria.
• Cleaning a sponge is one thing (and it usually involves a simple rinse). Sanitizing it is another. "The EPA has no approved test method for sanitizing sponges," explains Mary Gagliardi (aka "Dr. Laundry"), Clorox's in-house scientist and cleaning expert. “Sponges are not hard surfaces or textiles, so they don’t fit neatly into existing testing protocols to establish sanitizing efficacy.” That means even the strongest cleaners can’t officially claim to sanitize your sponge.

How to Clean (and Try to Disinfect) Kitchen Sponges

You can’t truly “sanitize” a sponge the way you would a countertop; however, you can clean them often and reduce bacteria. 

If your sponges get a lot of use in the kitchen, consider this a daily chore.

• Microwave Method: Wet the sponge first (very important, so it doesn’t catch fire), then microwave sponge on high for one minute. According to the USDA, microwaving your sponges may help to reduce 99.99999% of bacteria.
• Dishwasher Method: Place the sponge in the top rack and run it through the hottest cycle with a heated dry. This cleaning method won’t kill every germ, but it comes close. USDA estimated that the dishwasher can kill 99.99998% of yeasts and mold.
• Bleach Soak (for dishcloths, not sponges): Sponges don’t have an EPA-approved method for sanitizing, but dishcloths do. Dr. Laundry recommends: “Add 2 teaspoons Clorox® Disinfecting Bleach to 1 gallon of water. Soak the dishcloths for 2 minutes, then rinse and hang to dry.”
• Boiling Water: Much like the microwave method. Putting your sponge in boiling soapy water can kill some harmful bacteria, but it's not 100% and we can't condone it for getting a sponge clean. But if you try it, careful while handling the hot sponge.

Try not to use the same sponge for everything. Have one for dishes and another for counters. And if you’re cleaning up after raw meat, don’t risk it—throw it out.

How often should you clean a sponge?

If you’re using your sponge daily, clean it at least once a day using the microwave or dishwasher method. For heavy use (like cooking for a large household), you might need to clean it more than once.

How often should you replace a sponge or washcloth?

Use your judgement. A sponge isn't worth keeping around if starts to smell. Bacterial growth causes odors, changes in color, and can cause the sponge to break apart, but how often you replace it depends on how often you use them (and for what purpose).

Here are some signs it's time to get rid of your sponge or dishcloth:

• It smells, even after you clean it
• It’s slimy or has visible stains
• It’s falling apart or losing shape

Swedish Cloths vs. Layered Washcloths

• Swedish cloths are my favorite for cleaning counters and wiping up water. They're reusable, absorbent, and made from cellulose and cotton. You can toss them in the laundry or even the dishwasher. I like them because they dry quickly, and if maintained properly, they can last for months.
• Some newer cloths (like Keeki Cloth) have extra scrubbing layers and are made of materials designed to dry faster. Many materials are textured and good for scrubbing, but don't become entrapped with food particles as easily as traditional sponges and cloths. Many are dishwasher-safe and can withstand a hot cycle.

Whatever type you’re using, dryness is key. A dry sponge or cloth is less likely to grow bacteria. Don’t leave them sitting in the sink or folded in a ball... squeeze out the excess water and let them air dry flat or hang them over the faucet or sink edge.

FAQ

Can I use white vinegar to clean my sponge?

Sure, but it’s not very effective method for killing bacteria. It might help with smells, but it won’t disinfect the sponge.

Is microwaving a sponge safe?

Yes, but only if it’s a wet sponge. A dry sponge can catch fire in the microwave.

Can I sanitize a sponge with bleach?

Bleach kills germs, but sponges aren't approved by the EPA for sanitizing claims. That means we can’t say for sure how effective it is on sponges. It’s better used for dishcloths, which do have approved methods for sanitizing.