How to clean tough toilet stains (the zero waste way)

Here is a beautifully straightforward Zero Waste method to remove toilet bowl stains easily and inexpensively without using bleach, a chisel, or a power washer. 


Do you have limescale in your toilet bowl?

Wait, what is limescale? It’s a hardened build up of minerals that starts with a greyish cast and can turn an unsightly brown colour when rust develops on the outer layer.

I’d never dealt with toilet limescale before moving to Sydney. Our toilet developed this cement-like stain in the bottom of the bowl and at the water line over a period of about a year, in spite of regular cleanings. It would surely bother our rental agent when we eventually moved out, but furthermore, a brownish mark on the bottom of a toilet bowl looks unclean, no matter what the reason. Which is why I took a dramatic before picture, but ultimately decided against posting it.

But you know what bothers me more? Household chemical arsenals that could be mistaken for m#th labs. I resent the ease with which we can buy harsh chemicals when a few simple and inexpensive ingredients can do a fine job.

My approach to household cleaning

I strive for cleanliness, rather than sterility, the latter of which is a fool’s errand – nature hates a vacuum. I don’t buy commercially made surface cleaners, window cleaners, or toilet cleaners. Instead I use white vinegar, bi-carb (baking soda), castile soap, sea salt, and occasionally hydrogen peroxide. All are inexpensive and don’t irritate my respiratory tract. I refill everything but the hydrogen peroxide locally and, if motivated to, I could make vinegar, salt, and maybe even the castile soap myself.

These ingredients are fine for the outside of the bowl, but I struggled to figure out how to clean the hard scale on the bottom of the toilet bowl. Scrubbing harder wasn’t helping.

While searching some forums for tips, I came across a lot of dubious advice about how to remove the stains – use hydrochloric acid / WD40 / Coca Cola, use a chisel / screwdriver / sandpaper, replace the toilet, or my personal favourite bad idea: use a power washer….indoors. Our perception of the scale of the challenge frames the level of response we think it deserves. Looks like concrete? Try a jackhammer! Who knows, maybe these methods all work, but call me low-tech, it was this one infrequently mentioned solution caught my attention: citric acid.

What is citric acid?

Citric acid is found in citrus fruits, highest in lemons. It’s used in the kitchen for jam, tofu and cheese making, food dehydration, and more. It’s what makes citrus taste sour.

I was intrigued because it sounds gentler than chlorine bleach, and if the citric acid didn’t work on the toilet, I could use it in the kitchen.

citric acid from lemon

The test: can citric acid clean my toilet?

I bought a small amount of citric acid crystals from the supermarket to test. I experimented by adding a tablespoon to the bowl and left it for about an hour. The size of the stain reduced, but it wasn’t the overall miracle I was after. For the next attempt, I upped the dose to 35 grams of citric acid (about a third of a cup, eyeballed) and let it sit overnight.

In the morning, I saw greyish patches of debris floating on the water’s surface. A flush revealed the miraculous result: ceramic perfection. It worked! All the cement-like rock solid crud was completely gone, dissolved. And there was no scrubbing, chiseling, or power washing required. All this for a total cost of $1.40 (AUD).

Zero waste toilet bowl cleaner

I should mention that in drought-prone Australia, low flow toilets are the norm and there is only a small amount of water in the bowl (as seen in the pic) compared to North American toilets.

Would lemon juice work instead of citric acid?

Yes, probably, but you’d need lots of lemon juice to get the equivalent amount of citric acid. An ounce of lemon juice only has about 1.5 grams of citric acid, and this will vary from fruit to fruit. If you live where lemons are abundant, go for it. I could probably only buy two or three lemons for the same price, so citric acid is more cost effective.

Ultimately citric acid is not the only solution.The trick is using an acid on the limescale, so probably vinegar would work too. If you make kombucha, you can easily make vinegar. If you’ve used kombucha vinegar to clean the toilet, I’d be curious to hear about your experience.

Is this really a Zero Waste solution?

I didn’t buy the citric acid in bulk or unpackaged, but that’s less of concern to me because a Zero Waste approach is more than a question of packaging, it’s an overall less is more approach.

  • The crystals are sold in crystallised form, which means less cost to ship around, and less plastic packaging to move the weight of liquid.
  • I needed to use only a small amount to work.
  • I didn’t need to buy rubber gloves or a face mask to protect myself from chemical burns or respiratory damage.

A word of caution on DIY and ‘natural’ cleaners

I subscribe to the idea that we should reduce the volume and breadth of industrial chemicals we produce and use everyday. However, please keep in mind……

Natural isn’t chemical free or non-toxic

‘Natural’ cleaners are still made of chemicals. The widespread use of the term chemical-free bothers me because it’s scientifically inaccurate and reinforces the pervasive and damaging belief that natural is always better, and never harmful. That belief is harmful. Essential oils can be toxic, asbestos is a natural substance, etc. Chemicals are not by definition harmful and natural is not by definition safe. Science is not a religion, it’s just controlled testing, and believe it or not, some science people are testing things like the impact of vinegar on microbes. Useful stuff.

Some cleaners don’t play well together

The normal rules of chemical reactions apply to DIY cleaners. I don’t own bleach, but if you do, keep in mind that you should never, ever mix acids with bleach. Citric acid and vinegar are both acids. I would suggest labelling your cleaners with what is in the bottle what it shouldn’t be mixed with. You may know what’s in there, but your children, roommates, or partner may not.

Citric acid cleans toilets easily and cheaply

I felt over-the-top clever learning and applying this little hack and am excited to share it with you. Simple and inexpensive solutions are best, because Zero Waste should be accessible for everyone. Have you ever used citric acid for cleaning? I’d love to hear about it.

A few surprising uses for eggshells

Bill Gates thinks a chicken is the best investment you can make. While he doesn’t go into too much detail on the nuts and bolts, you can imagine it’s more to do with egg production than a particularly satisfying rotisserie meal. But it’s not just the chicken or the egg that have value, the eggshell too can be useful. A great example of how a ‘waste product’ is really just another raw material.


Scratching at the surface

My partner’s brother keeps chooks in their backyard and it’s fun to watch them sunning and perching. Chickens are perhaps an under-appreciated one of design of nature – egg making machines powered by food scraps and pasture grubs. If I could, I’d keep chickens at home. In the meantime, I buy eggs laid by pasture raised chickens, or at the very least, free range chickens.

This is a long way from what I used to do, which was look for the cheapest food possible. It did me well as a uni student, where leftover cash could fund my drinking hobby, but my view on this started to course correct after reading the Omnivore’s Dilemma, and generally learning more about food production systems. I now buy the best quality food I can afford and pay attention to animal husbandry involved. And I drink less.

The chooks matched the house….and the (not pictured) elderly owner.

Shelling out for quality

I justify spending $6 – $10 a dozen on pastured eggs because I know they are better for me, the chooks and the environment. How the animals are raised impacts on the nutrition of their output.

Via Sustainable Table: Eggs from poultry raised on pasture have 10% less fat, 40% more vitamin A and 400% more omega-3’s.

After I use an egg, I hold on to the eggshells and store them in the freezer until I plan to use them, bothering no one except my partner. He once asked why I was storing garbage in the freezer and I had to gently remind him that there is no such thing as garbage. The eggshells, apple cores, celery bits and citrus peels are all raw materials just waiting for a good way to be used.

Here are a few ways eggshells are useful long after the nutritious interior is gone.

Use eggshells in the garden 

They can go directly into your compost or they can be used to start seedlings and improve the soil.

eggshells for vermicomposting

Improve the soil In the soil, eggshells act as a slow release source of calcium, which helps to raise the PH of the soil (making it less acidic). Grind finely for best effect. Apparently this helps in vermicomposting if the bedding becomes too acidic. I have also read that the grit of the eggshells helps the worms, toothless creature that they are, to grind away at the food scraps.

Start a seedling There are plenty of ways to start seedlings – this Pinterest popular solution shows that half an eggshell can replace those small plastic punnets.

What aren’t they good for? Deterring slugs! According to this blog anyway (what you really want is diatomaceous earth).

Use eggshells in the kitchen

Clean the inside of a bottle Trust Tammy from Gippsland Unwrapped to find a Zero Waste and effective solution to a sometimes tricky task – cleaning out the grit from insides of bottles.

Clean a bottle with eggshells

It’s nice to know the minimalists among us could do away with a bottle brush. Since I already have a bottle brush, I use this trick whenever the brush doesn’t fit. Just add crushed eggshells and water into the bottle, and shake it like a Polaroid picture. It’s crazy how well this works.

Calcium supplementation Milkwood’s Kirsten Bradley adds an eggshell to water kefir ferments where it slowly dissolves over several batches. Each eggshell would have about 2000 – 2500mg of calcium, so you wouldn’t want to overdo the daily dose, especially if you’re getting a lot of calcium elsewhere in your diet or have heart issues. I don’t supplement calcium, but thought it an interesting way to achieve specific supplementation without the typically bottle and seal waste.

Use eggshells in…the bathroom?

Make tooth powder I make a tooth powder using calcium carbonate powder, clay, cinnamon, and sometimes bi carb or charcoal. I used to do the bi carb and coconut oil recipe, but it seemed a waste of oil and I didn’t like the idea of spitting oil into the drain pipes. All ingredients bought as refills from either the Soap Dispensary in Vancouver when I was there last year, or one of the bulk shops in Sydney. Since we don’t have a Soap Dispensary equivalent (tragedy really) in Sydney, finding a Zero Waste source of calcium carbonate could have proved difficult. Enter the ancient texts….

I’d read that ancient Romans used to grind eggshells for toothpowder. Clever, I thought, but I didn’t take action on this until I came across Zero Waste Chef’s post on making the same and then considered my lack of bulk calcium carbonate powder options.

How to find a good egg

  • If you can, buy or trade from someone you know. From a farmers market is a close second.
  • Watch out for misleading Free Range claims. In Australian, under current regulations, the stocking density can vary from 1,500 to 10,000 hens per hectare and no meaningful outdoor access. Animal welfare experts recommend 1,500. Sometimes this is listed on the carton, sometimes not. You can bet the cheapest free range eggs at the major supermarkets are produced with the max stocking density. More detail on the Choice website, including the names of brands that comply, those that don’t, and those that have been fined for lying.

How to tell if your egg is still edible

Australian eggs are often sold on the shelf, not in a refrigerated section. Once refrigerated, keep them there, but if they are not in the fridge when you buy them, there’s no real urgency in getting them into one, unless it’s really hot out or you plan to keep them for ages and ages. This also makes them handy for taking camping.

To see if your egg is still edible (and it probably is) you can check if it floats or sinks. Don’t eat a floating egg.

So give these ideas a crack or share in the comments any other uses you have for eggshells.