How to Clean a Sponge

Two Parts:Daily Maintenance Between Deep CleansDeep Cleaning

Using the kitchen sponge to clean the table, the dirty counter and possibly the stains on the floor can add bacteria to the surface you are trying to clean. Even sponges that appear clean can contain thousands of bacteria per square inch.[1] To avoid harboring germs, yeast, and spores in your sponges, clean them at least every three to four days using one of the following methods.

Part 1
Daily Maintenance Between Deep Cleans

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    Remove any remaining food scraps from the sponge.
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    Wring out the sponge as much as possible and place aside where it can dry completely. (Bacteria love moisture.)
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    Avoid cleaning the cutting board with it, especially if the cutting board has been used for raw meat.[2]

Part 2
Deep Cleaning

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Microwave Method

Caution: This method requires that your sponge does not contain metal.

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    Wet the sponge completely and do not allow it to dry. Caution: Some sponges are made of plastic material that can melt in a microwave even if the sponge is very wet. Place a paper towel underneath the sponge - if your sponge melts, this will make clean up much easier.
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    Put it into the microwave, and set it for at least one minute. According to a study by the USDA, microwaving for one minute significantly lowers bacteria counts and populations of mold and yeast more than other methods.[3] Researchers have also discovered that after microwaving for two minutes, more than 99% of all the living bacteria will be dead.[4]
    • It's a good idea to place at least a half-cup of water in the microwave with the sponge to be cleaned. This helps to protect your microwave emitter.
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    Remove and let cool before using. Caution: Squeezing the sponge before cooling can cause severe burns.

Dishwasher Method

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    Place it into the utensil compartment of the next wash and dry cycle. Allow it to remain for the entire wash and dry cycle.
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    Remove it after the washer stops. The sponge will now have 99.9998% less bacteria on it. [5]

Soak Method

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    One study suggests the soaking method is not as effective as other methods. But it still helps a great deal. [6]
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    You may wish to use a rubber glove to protect your hands while performing these steps.
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    Clean the sponge as well as you can using tap water and dish detergent. Rinse thoroughly under running water.
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    Make a solution of 10% bleach in a small bowl. Use hot tap water to maximize the effectiveness of the bleach (Chemistry 101 - hot water makes the molecules in the bleach more agitated, thereby increasing their effectiveness). A plastic food container you are intending to recycle is a good bowl to use.
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    Soak the sponge for 5 minutes, maximum 10 minutes. Squeeze the sponge at least a couple of times while it is soaking. This helps ensure the bleach completely penetrates the sponge, and aids the removal of organic debris (the very stuff you want gone).
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    Remove and rinse thoroughly under running water.


  • After microwaving the sponge, the steam and humidity produced inside the microwave loosens food particles and stains. Use a paper towel, dishcloth or washcloth after removing the sponge to effortlessly wipe away microwave stains!
  • Use cloth kitchen towels to clean up day-to-day spills and messes on countertops, floors, and tabletops. You will save money on paper towels and lengthen the sanitary life of your sponge.
  • After using the sponge, wring it out and wrap it in a paper towel to absorb any excess moisture. A more environmentally friendly and generally less wasteful way is to use a dish towel instead.
  • Add lemon juice or non-ammonia lemon kitchen cleaner to bleach solution to help cut the bleach smell. Using a scented bleach is also an option. To use rinse with cold water when finished
  • If you need to kill all spores (rather than just bacteria) microwave the sponge for 5 minutes. Be careful to make sure it is still wet, though, as the sponge can catch fire or melt.
  • Replace the sponge regularly. Buying a sponge labeled as germ-resistant can lower the amount of bacteria in your kitchen by 99.9%.
  • Instead of your sponge, use other materials to clean up raw juices from meat. Paper towels work well, but it may be more economical and environmentally responsible to use a separate dishcloth or washcloth.
  • The first time you microwave your wet sponge, it may smell very bad due to a buildup of mould or bacteria being killed on the sponge. Regular cleaning of your sponge reduces this.
  • When finished using the sponge, squeeze it thoroughly and allow to air dry completely between uses. Bacteria will die in a dried sponge. You can alternate between two sponges to allow for longer drying time and you can lean the moist sponge against backsplash or dish liquid bottle to allow for better venting/drying. [7]


  • Before cleaning in your dishwasher, check the manufacturer's instructions or web site. Some manufacturers and dishwasher repairmen do not recommend this method for cleaning sponges as parts may come off and lodge in the mechanism.
  • Don't microwave a sponge for longer than five minutes. It will become a fire risk.
  • When using the microwave method, touching or squeezing the sponge before cooling can cause severe burns. Take appropriate precautions to avoid getting burned.
  • Our bodies need bacteria in our environment to remain healthy. First, because some bacteria are beneficial. And second, because our immune systems need regular exercise to remain strong. This article is accurate, but excessive focus on cleanliness may make users less healthy in practice.
  • Do not heat a dry or slightly damp sponge in a microwave. The UK Royal Society for Prevention of Accidents does caution against using microwaves to clean a dry sponge.[8] The researchers said people should only try to microwave a damp sponge or dishcloth because if dry, it might start a fire.
  • You may find your microwave develops an unwashable stench after zapping a mildewed sponge. Make sure you open your microwave after zapping to let the microwave air out.
    • Cleaning your sponge regularly does not mean you can keep the same one forever! Make sure to regularly replace your sponges.

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