Why Just Washing Your Keens Won't Stop the Stink (And What Actually Works)

Evan Chymboryk Founder • B.S. Exercise Science

We’ve all been there. You spent a good chunk of change on a pair of Keens because they're the ultimate "do-everything" sandal. They handle the lake, the trail, and the backyard BBQ without breaking a sweat. But then, about a month into the summer, it happens. You catch a whiff of something that definitely isn't pine needles or fresh air. It’s the "Keen Funk."

So, you do what any sensible person does: you toss them in the wash or scrub them with dish soap until your knuckles hurt. They look great, they smell okay for an hour, and then—as soon as they get a little warm—the smell comes roaring back. It’s frustrating, right? You feel like you're failing at basic shoe maintenance. But here is the thing: it’s not you, and it’s not even the dirt. It’s the science of what’s happening inside that footbed.

Why Do Keen Sandals Smell So Bad After Washing?

Keen sandals smell after washing because the porous EVA foam footbeds trap skin cells and sweat deep within their structure where standard soap cannot reach. When the sandals get damp again, these trapped organic materials reactivate and release odors.

Keen uses a specific type of foam called EVA (Ethylene Vinyl Acetate). It’s fantastic for comfort because it molds to your foot, but it’s basically a high-density sponge for your sweat. Every time you walk, your foot presses down, pushing moisture and microscopic skin bits into tiny pores. A surface scrub only cleans the "roof" of those pores. The "basement" stays full of the stuff that causes that sour, vinegary smell.

According to the technical properties of EVA, the material is closed-cell but the texture often creates pockets where moisture sits. If you don't neutralize the source of the smell inside those pockets, the cycle just repeats. You aren't just fighting dirt; you're fighting a biological buildup that is literally hiding inside your shoes.

You don't need a chemistry degree to fix this. You just need the right tool to reach those deep-seated odors that a washing machine misses. This is the one we keep by the back door for the toughest cases:

What Is the Best Way to Clean Keen Sandals for Odor Removal?

The most effective way to clean Keen sandals is to hand-scrub them with a baking soda paste and a soft nylon brush, followed by a thorough rinse and an application of a natural essential oil deodorizer. This combination physically removes grime and chemically neutralizes odors trapped in the foam.

If you want to do this right, you need to be a bit more intentional than just a quick rinse. Start by grabbing a soft nylon brush (an old toothbrush works great too) and a microfiber cloth. Mix a little water with baking soda to create a thick paste. This is a classic move because baking soda is mildly abrasive and helps pull some of that "gunk" to the surface.

Apply the paste to the footbed and scrub in circular motions. Don't forget the straps! After you've given them a good workout, rinse them under cold water. But don't stop there. While they are still damp, you should apply a specialized spray like the Extra Strength Shoe Deodorizer Spray. The essential oils in the spray can penetrate the same pores the sweat does, providing a much deeper level of freshness than soap ever could.

Can You Put Keens in the Washing Machine?

Yes, most Keen sandals are machine washable on a gentle cycle with cold water and mild detergent, but they must always be air-dried away from direct heat. Frequent machine washing can eventually break down the adhesives and the integrity of the bungee lace system.

I get the temptation. Tossing them in the machine is easy. And for the most part, Keens are built like tanks. But there is a trade-off. The agitation of the machine can be hard on the stitching over time. Plus, if you use a detergent with harsh chemicals, you might actually be stripping away the natural oils that keep the materials flexible.

If you do go the machine route, put them in a mesh laundry bag first. This prevents the bungee cords from getting snagged on the agitator. And whatever you do, never—ever—put them in the dryer. Heat is the enemy of EVA foam. It will shrink your sandals and make the footbed brittle. I learned that the hard way with a pair of my kid's cleats, and trust me, "shrunken cleat" is not a look you want.

We compared our natural spray against the big-brand aerosols you'll find at the grocery store. The difference isn't just in the smell—it's in how it treats your expensive footwear.

How Do You Stop Sandals From Smelling Permanently?

To prevent sandal odor permanently, you must rotate your footwear to allow 24 hours of drying time between wears and apply a natural deodorizer immediately after each use. Keeping the footbed dry prevents the environment that odor-causing particles thrive in.

Maintenance is way easier than a deep clean. If you wear your Keens every single day without a break, they never fully dry out. And a damp shoe is basically a resort for smells. Try to alternate days if you can. If you can't, use a microfiber cloth to wipe down the footbed as soon as you take them off to remove excess moisture.

A quick spritz of Natural Citrus Tea Tree Shoe Deodorizer Spray every evening makes a world of difference. It takes five seconds, but it stops the "funk" from setting in. It’s much better to prevent the smell than to try and "kill" it once it has become unbearable. You might also want to check out our guide on why scrubbing alone doesn't work for a deeper look at this problem.

As one happy customer, Sarah, shared: "My son’s Keens were banned from the house. I tried everything. This spray is the only thing that actually worked and didn't just smell like 'fake flowers and feet'."

Are Natural Deodorizers Effective for Heavy-Duty Sandal Odor?

Natural deodorizers are highly effective for heavy-duty odors because they use concentrated essential oils like eucalyptus, lemongrass, and tea tree, which naturally break down odor molecules rather than just masking them with synthetic fragrances.

A lot of people think "natural" means "weak." But have you ever smelled raw tea tree oil? It’s potent stuff. These oils have been used for centuries because they actually work. Unlike those grocery store aerosols that just pump the air full of chemicals, natural sprays target the source. If you're dealing with a truly "toxic" pair of work boots or sandals, you might need something with a bit more kick, like the Natural Lavender Tea Tree Shoe Deodorizer Spray.

Is the natural route perfect? Mostly, but it does require consistency. Here is the honest breakdown of what you can expect:

At the end of the day, your Keens are an investment in your comfort and your adventures. You don't have to let a little thing like "the funk" ruin your favorite pair of shoes. By understanding that the smell is living *inside* the footbed and using natural tools to neutralize it, you can keep your shoes (and your mudroom) smelling fresh all season long.

If you're tired of holding your breath every time you take your shoes off, it might be time to switch up your routine. Start with a deep clean, let them dry properly, and keep a bottle of Lumi nearby. Your nose—and your family—will thank you.

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