How to Clean the Dirtiest Thing in Your Kitchen

Is your kitchen sponge more germ-filled than your toilet seat? At least one microbiologist thinks so. A survey of U.S. homes by the NSF (formerly the National Sanitation Foundation) found that 77 percent of sponges and dishcloths contained coliform bacteria (often an indicator of disease-causing bacteria); 86 percent had yeast and mold; and 18 percent had Staph bacteria, which can cause symptoms ranging from vomiting to life-threatening septic shock.

In short: Yikes.

Luckily, green cleaning guru Leslie Reichert has some simple tips for keeping your kitchen sponge, and everything it touches, clean and free of bacteria and mold.

1. Clean, then disinfect your sponge.

When we think about cleaning, we often think about bleach, but bleach is a disinfectant — not a cleaner. “One thing that people don’t realize is that you can’t disinfect something until it’s been cleaned,” says Reichert. So, put down the bleach and do this instead.

First, Reichert recommends cleaning with something gentle but effective, like castile soap, to remove food and dirt. (Normal dish soap will do as well.)

Then, sanitize the sponge. You can put it in the dishwasher when you run a load of dishes. Or, dampen the sponge and put it in the microwave on high power for 30 seconds to two minutes, depending on your microwave’s strength. Just be sure it’s damp, otherwise there’s a fire risk.

Reichert also suggests soaking sponges in white distilled vinegar, lemon juice, or hydrogen peroxide. Since hydrogen peroxide can be strong, Reichert suggests diluting it by pouring some into a bowl, adding the sponge and then filling the bowl the rest of the way with water.

Finally, make sure to thoroughly rinse the sponge after disinfecting.

2. Keep your sponge dry.

Since dampness plays a big role in a sponge’s bacteria growth, it’s important to store a sponge properly. Hint: Not at the base of a wet sink.

Reichert likes to store her kitchen sponge upright, ideally near a window so that air flow and sunlight can help keep it dry. She uses this Kohler sponge holder.

3. Replace your sponge often.

Even with careful storage, cleaning and disinfecting, replacing your sponge every two weeks is a good rule of thumb. “I know that seems like a short period of time for a sponge that looks good, but after two weeks it’s starting to accumulate bacteria and it’s not healthy,” says Reichert.

4. Use a sponge alternative.

An exception to this two-week rule are sponges made from an alternative materials. Reichert recommends the BioBob sponge. Made with organic pigments and “enviro-ester”—an American-made polyester resin free of harmful chlorofluorocarbons and formaldehyde —they don’t promote bacteria growth like wood pulp sponges.

“I have used one of their sponges for 6 months and it does seem to get better the older it gets,” says Reichert. “There is no smell and it doesn’t feel slimy or seem to have a film. I clean them in the microwave and the dishwasher and they seem to come out feeling brand new.”

Also in Reichert’s green cleaning arsenal are Skoy Cloths, which she describes as a combination of a sponge and an ultra-absorbent paper towel that dries very quickly. Each biodegradable, compostable cloth is equal to 15 rolls of paper towels in the average home. Plus, they’re chlorine-free, unbleached, and non-GMO so they’re eco-friendly. You can clean and disinfect Skoy Cloths as you would sponges, or run them through the washer and dryer.