The Pitfalls of Plastic Sponges — And How to Wash Your Dishes Cleaner and Greener

The Secret Life of your Kitchen Sponge


Ah, the kitchen sponge. Nearly every household in America has one, yet most of us don’t know much about them. What are sponges made of? How do you sanitize a kitchen sponge? And what happens to a kitchen sponge when you throw it away?


Here’s the gist for you: 


➢ Modern kitchen sponges are typically made of cellulose (read: tree fibers) and plastic.


➢ While most people think you can just clean a sponge in soapy water or a microwave, it’s more complicated than that.


➢ And when you do throw a plastic sponge in the garbage, it sits in a landfill for an unknown length of time. Seriously, no one knows! Based on the plastic materials, estimates range from 100 to 1,000 years. 


Here at Cloud Paper, we’re all about reducing waste and offering sustainable solutions to common household items. Plastic doesn’t really decompose and also sheds microplastics into the ecosystem, so you know we’re not a fan of the material. 


But plastic sponges are so useful! We’re not going to deny it. What we are going to do is to discuss their pros and cons and what alternatives you can use instead.


Let’s dive into the nitty gritty of kitchen sponges — the good, the bad, and the ugly… and I’m sorry to say, it does get ugly. 

The Secret Life of Your Kitchen Sponge 

Have you ever flipped over a nice looking log only to discover a teeming world of worms, millipedes, maggots, and more? There’s no easy way to break this to you, but the surface of your kitchen sponge is like the untouched bark of a decomposing log. It may look nice on the outside, but there’s a thriving little world of bacteria within. 


The kitchen sponge is a haven for bacterial life. And the internet is bursting with comparisons that will twist the gut of even the most steel-stomached person. 


But there’s no denying the science.


A team of microbiologists led by Dr. Egert at the University of Furtwangen in Germany determined that the kitchen sponge is among the dirtiest places known to mankind. The primary qualification for the title is its bacterial density — meaning the amount of bacteria per cubic inch of the sponge.1

 The kitchen sponge is a haven for bacterial life


The team found more than 362 different species of bacteria living in standard kitchen sponges. Dr. Egert sums it up in this gag-worthy statement about the bacterial density:


“That’s the same density of bacteria you can find in human stool samples… There are probably no other places on earth with such high bacterial densities.”




Okay, so… Shocking. Disgusting. Alarming. 


While it may be tempting to run downstairs and throw your kitchen sponge out the window, scientists say that typically, those bacteria won’t harm you. But if you have a weakened immune system or a particularly dirty kitchen sponge, you could end up with an infection or common illnesses like food poisoning. 


So, maybe don’t panic. But it might be time to start looking into alternatives to sponges. To find a better option, it’s helpful to understand why kitchen sponges are such bacterial cesspools. 

Why Are Kitchen Sponges So Dirty?

It’s a combination of factors, but essentially the kitchen sponge is a convergence of several roads… all leading to poor hygiene and bacterial haven. 


Here are the main culprits: 

Kitchen Sponges Are Used for Everything

Kitchen Sponges Are Used for Everything


You wash your water glasses with them but you also wash your meat covered cutting board. You might wipe down the stove and counters with your kitchen sponge. And you might even clean your dog’s food bowl with it. 


Remember that sponges are intended to absorb things, so when you wipe your sponge along a surface, it picks up everything in its path. 

Sponges Are Almost Always Wet

This is crucial because bacteria love warm, wet places. If you use your sponge throughout the day — it’s likely never dry. Especially if you leave it at the bottom of the sink or don’t bother wringing it out thoroughly.  

Traditional Sponges Are Dense and Thick

Not only does this keep the sponge from ever really drying out, it also makes it difficult to disinfect the inside.

Can’t You Clean Your Sponge in the Microwave?

This is a common reaction to learning how dirty your kitchen sponge is. Sure, it might be full of bacteria, but you can just clean that sponge in the microwave… or in a bowl of bleach… or in the dishwasher… right?

Unfortunately, cleaning your sponge in the microwave may be worse than not cleaning it at all. 


In fact, Dr. Egert and his team found that sponges that had been “sanitized” in the microwave actually had worse bacteria than those that had never been subjected to the method. 


Here’s why: 


Regardless of your chosen cleansing routine, it’s likely that some bacteria survive the ordeal. The bacteria that survive are the strongest — and usually most sinister — of the bunch. And now that all of its neighbors have burned off, there’s even more space for that bad bacteria to grow and multiply. 


Dr. Egert and his team suggest instead of cleaning your sponge, you should throw it away. In fact, they recommend replacing your kitchen sponge every single week — AND they recommend replacing it more often if it starts to stink, since that smell can be a sign of bad bacteria growth. 


But since plastic sponges take 100 to 1,000 years to decompose, that’s not a very earth-friendly prospect. So what do we recommend instead?

Eco-Friendly Sponge Alternatives 

There are a number of eco-friendly sponge alternatives with a variety of pros and cons, so it really comes down to your preferences. It’s important to pick a sustainable sponge alternative that you enjoy and will actually use. 

Natural Sea Sponges

Sea sponges are the natural precursor to modern sponges and were used for years before the invention of the plastic sponge. These organisms grow along ocean beds and are a biodegradable and renewable resource. 


Natural sponges may be better than plastic, but we prefer to let the sea sponge be and go with one of the other eco-friendly sponge alternatives.


Unfortunately, there are a few problems with natural sea sponges: 


  • Sea sponges live in sensitive habitats where they provide shelter for fish and other creatures. A harvested sea sponge will technically regrow itself, but it takes ~3 years before it’s full grown again. 
  • Although they don’t have nerves or circulatory systems, they’re technically animals and therefore not a good option for vegans. 
  • While they aren’t currently listed as endangered, sea sponges were hunted to near extinction in the 1900s.2

Natural sponges may be better than plastic, but we prefer to let the sea sponge be and go with one of the other eco-friendly sponge alternatives. 

Biodegradable Sponges Made of Natural Fibers

If you really like the convenience and feel of a traditional sponge, this might be a good option for you. Biodegradable sponges are made from plant fibers like coconut, cotton, and cellulose (note: this usually means tree fibers). 


These sponges fall victim to the same pitfalls of synthetic sponges, so you’ll want to take precautions against bacteria. Remember, try to let them fully dry to limit bacterial growth, and replace them frequently. 


The plus side is biodegradable sponges are biodegradable. So when you’re done with one you can cut it up into small pieces and throw it in your compost. (Don’t have a compost? It’s super easy! Check this out.)

Cotton Dishcloths 

Cotton dishcloths are a reusable alternative to using sponges altogether.


Cotton dishcloths are a reusable alternative to using sponges altogether. They are made from natural materials and therefore biodegradable (although you’ll find they take a long time to decompose in a home compost). Unfortunately, they also take a long time to dry, meaning they are subject to bacterial growth. 


Cotton dishcloths can be reused for a very long time, however they have the same fatal flaw as sponges — if you don’t remove all the bacteria, you could be creating a monster. The internet is full of suggestions to properly sanitize your dishcloths, from boiling them on the stove for 30 minutes to leaving them out in the sun all day. But if you want a truly sterile option, cotton dishcloths may not be your best bet. 

Swedish Dishcloths

Swedish dishcloths are like a cross between a reusable dishcloth and a biodegradable sponge. Made from a mix of cotton and cellulose, the “Swish Cloth” as we affectionately call it is an absorbent cloth that is thin and quick-drying.



Because Swedish dishcloths dry quickly, they are less habitable to bacteria.


And since they are thin, they are easier to properly clean. Swedish dishcloths can be cleaned in the dishwasher or laundry and reused for up to 4-6 months, though if you’re using them for dishes, we still recommend replacing them more often. 


Swedish dishcloths can also be cut up and composted in a home compost and won’t take as long to decompose as cotton cloths will. 

4 Sustainable Tips for Extending the Life of Your Sponge or Dishcloth

If, like us, reading this article has made you question your own dishwashing implements, you might be tempted to try a semi-reusable option like a biodegradable sponge or Swedish dishcloth. But if, like us, you also want to use that sponge or cloth to its fullest extent before sending it off to its dirty end (pun intended), we’ve put together a few tips to extend the life and cleanliness of your chosen tool. 

1. Allow the sponge or dishcloth to dry well and often. 


Bacteria need moisture to grow and reproduce, so allowing your sponge or dishcloth to fully dry on the reg is essential to prevent bacteria from multiplying in the first place.

2. Remove leftovers and food debris before washing dishes.


The bacteria in your sponge and dishcloth can come from food debris, so scraping your dishes and rinsing with water before scrubbing will limit the contaminants. 

3. Avoid using your sponge or dishcloth for anything but dishes.


Experts suspect this where a lot of bacteria is added to the equation. Using your dish sponge or dishcloth to wipe counters, clean up floor spills, and soak up the chicken juice that spilled over the edge of the cutting board is a big no-no. Give your sponges or cloths specific jobs, and try not to mix them up.

4. “Downgrade” your sponge or dishcloth to reuse it.


If each sponge or dishcloth has a specific job, you can “downgrade” your dish scrubber to become a floor spill wiper or a shower cleaning rag. This helps extend the life of your sponge or dishcloth while maintaining a sanitary kitchen and keeps any potential contamination to surfaces that are less likely to be licked. 



Remember the main point is to reduce your exposure to potentially harmful bacteria — not to live in a sterile bubble. (Seriously, they’ve done studies on this! You actually need to be exposed to a certain amount of bacteria to keep your immune system healthy and strong!3)

If you’re ready to replace your kitchen sponge with a sustainable alternative, give Cloud Paper’s Swish Cloths a try!

Check out these positive reviews from several of our customers: 


Review from CP customer, swish cloths are soft and absorbent
Review of CP swish cloths: Using swish cloths saves on paper towel usage
Review for CP Swish cloths, great for surface cleaning