How to Clean a Sponge

APRIL 30TH, 2019
How to Clean a Sponge

By now, it should come as no surprise to you that the sponge in your kitchen could be harbouring several thousands, potentially millions of bacteria and mold spores.

Gross, right?

No one likes the idea of cleaning their dishes with a germy-filled sponge.

Why You Need to Clean your Sponge

While it might be a bit frustrating to realize that you must also clean the cleaning items in your household, when you stop to think logically about why, it makes sense.

The kitchen sponge is what you use to scrape off or pick up the stuck-on, sticky, gross leftovers from your meals.

All of those food scraps, sauces, and other grime that you clean off of the dishes end up accumulating within the sponge you used to clean up the mess in the first place.

Kitchen sponges are an ideal environment for bacteria and mold to live in.

Moisture, humidity, and some sort of organic material is all most microbes needs to thrive.  Your kitchen sponge is a place with all three.

Friends, this is why your kitchen sponge smells bad.

How to Clean a Sponge

Bleach is the most effective way to clean a sponge.

In an analytical study conducted by The Good Housekeeping Institute, bleach was found to remove 99.9% of bacteria living within a regular kitchen sponge.

How to Disinfect a Sponge with Bleach

To clean your dirty sponge with bleach, mix ¾ cup of bleach into 2 litres of water.  Let the sponge soak for at least 5 minutes. Thoroughly rinse with water. That’s it.

Cleaning your sponge with bleach is the most effective for removing bacteria and is quite simple.  However, there is caution to be had when using bleach, especially when using it as a tool to clean items which you place your food on.

Also, you might not have bleach in your household.

So, here are a couple other quick and easy ways to clean your kitchen sponges at home.

Cleaning a Sponge with Vinegar

Soak your sponge overnight in a mixture of 1 cup hot water, ½ cup white vinegar, and 3 tablespoons salt. The next morning, squeeze the sponge out several times to get rid of the accumulated cleaning liquid.  Rinse thoroughly before use.

Cleaning a Sponge in Microwave

Put a wet sponge (with an emphasis on wet, DO NOT put a dry sponge in the microwave, it could set on fire) in your microwave and heat it on the high setting for 1-2 minutes.

Make sure you stay watching the sponge and do not walk away while it is in the microwave.  Microwave settings differ greatly from model to model.  You do not want to risk the sponge setting on fire if left inside the microwave for too long.

Cleaning a Sponge in Dishwasher

The dishwasher is also an easy and effective way to disinfect a sponge.  It kills 99.9% of kitchen sponge bacteria.

Simply add your sponge to your household dishwasher while running a regular load.  Ensure that you are using the ‘heated dry’ setting to maximize the effect.

How Ultra-Fresh Can Help Keep a Sponge Clean

By incorporating an antimicrobial agent into the sponge during the manufacturing process, the growth of odor-causing bacteria and mold are prevented before they can take hold and wreak odor-havoc.

The result is a kitchen sponge that doesn’t smell.


How Does an Anti-Mold Treated Sponge Work?

Have you ever had a kitchen sponge that smells like mildew?  Ick.  Ultra-Fresh can help combat those musty kitchen sponge smells.

Here an example of cellulose sponges after testing via the AATCC method 30, part III antifungal test method using Aspergillus niger.

Ultra-Fresh antimicrobal treated cellulose kitchen sponge
Cellulose sponge with Ultra-fresh treatment
Untreated kitchen sponge with mold
Untreated cellulose sponge tested using the AATCC Method 30, III

As you can see from the photos, the untreated sponge is covered in mildew growth after the 7 day incubation period. Alternatively, the antimicrobial treated sponge prevents unwanted mold growth, along with their funky odors.

How Does an Antibacterial Treated Sponge Work?

Now, how does Ultra-Fresh fair against odor-causing bacteria that are so stinky, they trigger your gag reflex?

The graph below demonstrates how an antibacterial sponge performs over time and after use.

The same amount of bacteria were added to an antimicrobial sponge, the same sponge after squeezing in dishwater 500 times, and also a sponge without an antimicrobial treatment.

As per the ISO 20743 test method, the samples were incubated for 24 hours at 98F/37C (body temperature). Afterwards, the number of bacteria remaining were determined.


Does antibacterial kitchen sponge work?
Does an antimicrobial kitchen sponge work?


The bacteria on the untreated kitchen sponge grew exponentially (from about 50,000 to over 400,000!).

However, the Ultra-Fresh treated antimicrobial sponge, had 99.9% fewer bacteria as compared to the untreated sponge after the same time period – even after 500 squeezes in dishwater!

Therefore, the conclusion is very simple: fewer bacteria = less kitchen sponge smells.

The addition of antimicrobial technology delivers a kitchen sponge that doesn’t stink.

Clean or Replace?

There comes a point in every sponge’s life when no amount of cleaning can return it to a cleanliness level appropriate for reuse.

If you are using a sponge that does not contain an antimicrobial, you really should be throwing out and replacing it every two to four weeks, depending on how much it gets used.

If your dinner plans usually consist of picking up take out, or you eat breakfast on your morning commute every day, you might be safe at the latter half of that time frame.  However, an untreated sponge should never be in your sink for more than a month.

If you are using an antimicrobial kitchen sponge, the end-use life becomes considerably longer, especially when cleaned routinely.

An antimicrobial kitchen sponge is a huge win for the environment since sponges are thrown out less frequently due to unbearable kitchen sponge smells.

In addition, since fewer sponges are required over time, antimicrobial treated sponges are beneficial to consumers’ bank accounts.

Note: Ultra-Fresh is not incorporated into items to control illness-causing bacteria.  The intent of the Ultra-Fresh antimicrobial feature is to prevent the growth of bacteria and mold that lead to stains, odors and product degradation.

Our Antimicrobial Expertise

Thomson Research Associates (TRA) is a global leader in the field of antibacterial, antifungal and antimicrobial, and anti-dust mite treatments, providing antimicrobial protection to finished products for over 60 years.

We are committed to helping our clients deliver fresh, durable, innovative and safe products by providing antimicrobial additives and treatments for fabrics, polymers, foams, coatings and more.


We are US EPA registered, BPR compliant, Oeko-Tex listed, and our products comply with all regulatory requirements of each country where they are sold.


Learn more about us or contact us for more information.

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