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We are answering a very popular question for you today: how do I clean mold stains from grout?

This question has been asked many times over the years, so I have been working on the best tips and information over the last several months.

Obviously, bleach is always a popular choice, but most people want to do something without bleach!

Chlorinated bleach comes with risks in various areas, but you can head to this post to read more about that!

For now, let’s check out how to clean mold stains from grout without bleach!

How To Clean Mold Stains From Grout (Without Bleach)

The chemist paste from the eBook is the key! We are sharing the recipe in this blog post with you today, but it is also found on page 14 of the eBook.  We call it “chemist paste” because it is such a powerful combination of household ingredients, it is so effective at whitening, scrubbing, and more.

Make sure you are following us on Instagram for more cleaning tips, videos, and behind the scenes! We go into a lot of detail and have great daily tips there including a video for this solution and a highlight dedicated to it!

So, what household items can I use to clean grout? All you need is two simple ingredients.

Homemade Grout Mold Stain Remover:

• Hydrogen Peroxide (Regular 3%)
• Baking Soda

Directions:

1. There are a few methods for creating the paste. First, add some baking soda into a bowl. Lightly spray peroxide onto the baking soda until a thick paste is formed. Almost like toothpaste (first picture in blog post shows texture).
2. Apply the paste to the grout area needing attention, and let it sit a 5-10 minutes (or as long as you would like).
3. With a tooth brush or small cleaning brush, scrub vigorously in small circular motions.
4. Rinse

Alternative method if the grout is in a horizontal position: First, sprinkle baking soda onto the grout, next lightly spray peroxide until a paste forms. Let this sit a few minutes, then follow instructions above for scrubbing.

The methods you use will depend on if your grout surface is horizontal, or if it is vertical on the wall or shower.

Does This Solution Kill the Mold Too?

Yes, it can kill the mold since peroxide is anti-microbial. We go into more on that in the science section below. If you have bad mildew or mold buildup on caulking, grout, or tile, you can use our two ingredient mold killer first before this solution. Our two ingredient mold remover will kill mold and mildew spores on almost every surface. This chemist paste solution is going to be more of a cleaner and a whitener for grout. I use both often. Just a quick tip!

Does this leave residue?

I have ever had issues with residue in all the ways I have used this solution, but a reader commented recently she had to rinse it many times to get the baking soda haze off. If you are using this on a different type of grout that isn’t sealed or is much more grainy, just follow up with hot soap water. Or you can also spray rubbing alcohol on the area. Each time I use this solution, there is almost nothing left after I scrub the area. If there seems to be a little pigment left from the baking soda, don’t worry, it also can wear off even just after a few hours.

I just wanted to add this tip in there if anyone had concerns about this.

Any Mold Spots Remaining?

If there is a hint of anything remaining, I also love following up with our homemade Lysol which is straight peroxide.

Spray the area with DIY Lysol spray, then scrub again.

This works for almost all surfaces we have tried it on!

What if this doesn’t remove the mold inside the grout?

Something to keep in mind is grout can be damaged overtime. It might be more than mold stains, and it could be missing grout. If you think this is the case, it is really important to reach out to a professional tile person to see about replacing the grout.

When we did our master bathroom remodel,  I learned from our tile guy that damaged grout is a serious issue. He repaired some of our other areas and removed the grout with an acid, then replaced it with new grout.

Anyways, just an important tip to keep in mind.

Is hydrogen peroxide safe for grout?

Peroxide is one of the best household cleaners because it is neutral. It isn’t acidic like vinegar which eats away at grout.

So, how does hydrogen peroxide and baking soda work to remove grout?

While we have different grout cleaning hacks, this is probably the best method I have used! And the best part about this mold removal from grout method? The science!

Hydrogen Peroxide

One of the neatest household chemicals for cleaning is good old-fashioned hydrogen peroxide. This solution is an anti-microbial, so it destroys things like mold. It also is oxygenated bleach, so it can whiten and minimize stains on surfaces!

We love peroxide on Chemistry Cachet, and you can head to this cool blog post to learn more about hydrogen peroxide and other things you can use it for.

Baking Soda

Baking soda is also an anti-microbial. It has many chemical properties making it a great cleaning tool, but the key in this solution is how it enhances the whitening power of hydrogen peroxide. You can read a detailed breakdown of baking soda in our post here.

Is it safe for all surfaces?

Yes it is! The great thing about this reaction is it turns into water and a salt. So, it is safe for surfaces.

H₂O₂ + NaHCO₃  → H₂O + NaHCO₄

Here is the area below the shower bar. I used the chemist paste, scrubbed it, then did a second treatment. After that, I just followed up with the DIY Lysol spray. If there is a little baking soda residue left, that is okay! It will rinse off when someone takes a shower.

I’m sorry the angles aren’t the exact same (some people get upset when my before and after pictures aren’t identical angles lol). It can be challenging to do blog post experiments and take pictures with my cute little assistant “helping me” :). But she makes everything more fun, so I am thankful for her help.

Can This DIY Grout Cleaner Work On Other Surfaces?

We plan to do another blog post series over this wonderful chemist paste, but yes, it works for so many surfaces! After I mixed up this solution for our blog post today, I used the rest to scrub the sink and around the faucet area. It has scrubbing power and removes all types of stains. In the eBook, we use it for things like baking sheets and pans with burn stains.

I hope you enjoy using this! I have been using this mix for 10 years now, and it is always a favorite!

 

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