This Tiny Laundry Tweak Helps Keep Towels Mildew-Free | Reviews by Wirecutter

By Caroline Mullen

Caroline Mullen is a writer focused on cleaning and organizing. Every rug in her apartment is machine-washable, but you can blame her dog for that.

Something I’ve had to come to terms with when it comes to living with other people: Not everyone shares the same standards for cleanliness as you do. And no amount of needling and nagging will change that.

Even my fiancé, Jeffery—whom I consider to be tidier and even more fastidious with organization than I am—has his undesirable habits. But the thing we argue about the most? His bath towels always seem to get that unmistakable mildew smell faster than mine.

It’s a maddening issue because we haven’t been able to figure out exactly why his towels get funkier faster.

We’ve run this through every possible scenario we can think of: Does he not drip-dry as much as I do before getting out of the shower? Does water cling more tightly to bodies that have more hair? Does our bathroom have such poor circulation that our towels don’t get dry enough? Or is my sense of smell so disturbingly keen that I’ll never make peace with the odors in our house?

While the last bit is probably true (I am plagued with my mother’s bloodhound nose), we haven’t landed on anything concrete that would cause this discrepancy in towel smells.

We have tried a number of solutions, however, including: switching to waffle-weave towels that apparently dry more quickly (nope), draping towels over the shower-curtain rod for maximum airflow (helps but doesn’t solve the problem), and even washing towels after every single use (exhausting and kind of wasteful).

In the end, I’ve discovered that the answer to our bath-towel woes is much more straightforward than an exhaustive investigation might reveal, and it’s certainly more cost-effective than tossing our towels whenever the mildew odor lingers. The solution is actually quite simple: a scoop of borax and a hot laundry cycle.

I always have a box of Borax in my laundry room, and this one is nicely priced and widely available.

I first became acquainted with borax when “laundry stripping” was dominating peak-pandemic social media feeds.

Laundry stripping involves filling a tub up with scalding hot water and then adding ½ cup borax, ½ cup washing soda, and a small amount of detergent. Clothes are swished around in this solution and left for four or more hours to soak, and the result is usually a tub full of dingy water. While laundry stripping certainly does aid in removing detergent buildup, hard-water buildup, and even our own body oils, it’s also rather harsh on clothing, and when it comes to dark fabrics, it might remove some dyes, too.

Back to borax, though. Also known as sodium borate, borax is a naturally occurring mineral of boron, sodium, and oxygen. It’s generally sold in powder form as a laundry booster and cleaning agent, and people also use borax as an insecticide, because it is considered less toxic to humans and pets than commercial pesticides.

(Some products containing borax are banned in the EU because the European Chemicals Agency found that high levels of exposure to it “adversely” affects “fertility and development” in animal research. Borax is not banned in the US, but it may cause eye irritation, and it’s poisonous if ingested. Like many cleaning products, it should be stored securely and kept out of reach of children.)

I reached out to Andrea Barnes, a Wirecutter writer who tackles all things fabric care, to get the nitty-gritty. She explained that borax can be used to brighten and deodorize laundry, and she said that all of Wirecutter’s top laundry-detergent picks include sodium borate, aka borax, in their ingredients. These detergents are high-performing for a number of reasons, but sodium borate definitely contributes to their stain- and odor-fighting abilities.

To understand how borax increases the efficacy of laundry detergents, however, first we need a little background on how detergents work. Detergents typically combine surfactants (which pull soils off of fabrics); multiple different enzymes (each one breaks down specific types stains, like grease or grass), oxidizing agents (like hydrogen peroxide), which act as a bleach alternative, since bleach deactivates enzymes and can be harsh on fabric; polymers (to suspend dirt and prevent it from redistributing onto fabric); and antifoam agents (to keep suds from overflowing).

Still with me? When added into a detergent’s formula or as a “booster” in powder form, sodium borate (which is, remember, just borax) is particularly helpful in stabilizing the enzymes that break down stains and odors—i.e. cleaner clothes.

Andrea asked what detergent I’ve been using at home, and when I told her it was Mrs. Meyer’s, a light bulb went off. I’ve been using Mrs. Meyer’s laundry detergent for about a year now, because the light fragrance was enough to scent our clothes but not send me into a spiral of sneezes. But Mrs. Meyer’s doesn’t include sodium borate in its formula. So it makes perfect sense why the addition of borax to my regular laundry cycles made a huge difference in cleaning power.

“Mrs. Meyer’s detergent plus a scoop of borax is actually very similar to Tide Free & Gentle,” Andrea explained. That’s because the sodium borate in Tide products is indeed used to stabilize the enzymes that really go to town breaking down odor and stains. It also makes perfect sense that I found a hot laundry cycle was more effective, because Mrs. Meyer’s instructs users to wash most clothing in hot or warm water, unlike Tide products that work exceedingly well in cold water.

There’s also a possibility, Andrea theorizes, that the essential-oil blend in Mrs. Meyer’s detergent was leaving residue on the towels and in the washing machine, creating pockets for bacteria to hide in both of them. If this is the case, the combo of hot water and borax likely strips the towels of this residue and cleans the machine at the same time.

Andrea is sensitive to fragrances, like I am, so she suggested that I try a cold cycle with Tide Free & Gentle for our stinky towels and see how it compared to doing a load using hot water, Mrs. Meyer’s, and borax. As someone who takes pride in effective cleaning, I was simultaneously pleased and miffed by the results.

What this detergent lacks in fragrance it makes up for in cleaning power.

As it turns out, Tide Free & Gentle was just as—if not more—effective at dislodging lingering smells from our towels as my original method. I’m not too big to admit when I’m wrong, though, and it’s no real surprise that the conclusions reached through Andrea’s stringent testing and research proved quite accurate.

Here’s the thing: Both methods have their pros and cons.

While Tide Free & Gentle certainly gets the job done, I find that I miss the familiar and cozy scent of Mrs. Meyer’s Rain Water Detergent. I also recognize that when it comes to getting things clean, fragrance doesn’t have any real benefit, and it might even be irritating my allergies. But it’s probably going to take some time for me to detangle that association in my brain.

If you want exceptional odor-removing power, and you aren’t particularly sensitive to fragrance, Andrea recommends our top pick, Tide Ultra Oxi.

That said, my original method does work, and I do like having the option of including or not including borax in different loads of laundry. “It’s definitely possible that the combo of hot water, borax, and Mrs. Meyer’s works really well for you,” Andrea said, and it might also be because borax aids in neutralizing water pH and softening hard water. And I do really love when clothes come out freshly scented—I’ve been conditioned, okay?

But now I have a hulking, Costco-size jug of Tide Free & Gentle to get through, and I also have half a bottle of Mrs. Meyer’s and about a pound of powdered borax burning a hole in my linen closet. So I’ll be using both methods, trading on and off for the next month or so, and eventually (hopefully) training my brain to not associate fragrance with clean, and instead to just be grateful that Jeffery’s mildewy towels are no longer an issue.

This article was edited by Megan Beauchamp and Catherine Kast.

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Caroline Mullen

Caroline Mullen is a staff writer reporting on cleaning and organizing at Wirecutter. Though she’s waging a constant battle against the dog hair and dust bunnies in her apartment, she’s not willing to scale back on tchotchkes to make it easier. It also takes her two to three business days to complete a load of laundry—but she’s made peace with that.