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Your travel tumbler lid is probably full of mold—here's how to clean it

Pass the dish soap, please

Tumbler Credit: MilanExpo/Getty Images

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How do you take your coffee? If you're like me, you like it black. Or maybe you stir in cream and sugar. Or maybe you prefer a splash of almond milk. Or maybe you're one of those tea-drinking people instead. But no matter your beverage of choice, if you're sipping it from a travel mug, you could be ingesting more than just your morning brew.

According to a viral Facebook post, there may be dangerous mold growing in your tumbler's lid. After hearing about multiple infections that were caused by bacteria in travel cups, one woman removed the seal of her own Yeti mug and found a disgusting surprise: It was coated in black mold.

Before you rid your cabinets of all your travel tumblers, we've broken down exactly why your cups might not be as clean as you'd think and how to properly sanitize them so they stay mold-free (spoiler alert: the answer is not "put them in the dishwasher").

What causes mold to grow in the lid?

Mold thrives in dark, damp places—just like that hidden crease between your lid and the removable seal that rarely (if ever) sees the sunlight. And if you never take the seal off when you're washing your tumbler, moisture gets trapped inside, making it the perfect environment for mold spores to grow.

Eek! There's mold in my tumbler. Should I panic?

Credit: Tinatin1/Getty Images

Mold-free tumblers, FTW.

Not necessarily. "Dirt/mold is gross (and obviously everyone should be keeping things clean) but unless you have a compromised immune system or literally never clean out your bottle, you're probably also not going to get sick from it," our Kitchen & Cooking Editor Cassidy Olsen says. "Stay on top of things, sure, but there's no need to panic."

That being said, if you find mold in your lid and you've been experiencing any not-so-great symptoms or feeling sick, contact your doctor immediately. According to the USDA, "Some molds cause allergic reactions and respiratory problems. And a few molds, in the right conditions, produce 'mycotoxins,' poisonous substances that can make people sick."

Here's how to clean your travel tumbler

Credit: Kathleen Finlay/Getty Images

So fresh, so clean.

Because no one wants their coffee with a side of mold, we asked Olsen to share her top tips for washing out a travel tumbler. "I think being lazy and leaving those bits on is what leads to mold growth," she warns. Below is her simple four-step process for keeping your cups clean.

1. Take the whole thing apart.

Break your tumbler down into as many pieces as possible before you start washing. That includes disassembling any rubber seals and exterior protection as well.

2. Use warm water and dish soap.

Always use hot, soapy water to clean. While some people may use cold water in an attempt to save money, warm water actually makes dish detergent more effective at cutting through oil, bacteria, and, yes, mold.

3. Get into hard-to-reach places.

A haphazard swipe around the inside of your cup isn't going to get the job done. You'll need to thoroughly clean out every nook and cranny of the different parts, which Olsen recommends using pipe cleaners or Q-tips to tackle.

4. Dry all of the pieces thoroughly before you reassemble it.

You could have the most sparkling clean tumbler imaginable... but if you don't dry the parts before putting it back together, you'll end up with a moldy mess in no time. Let the pieces dry completely overnight or thoroughly towel-dry them, making sure there's no excess water hiding in the creases of the seal.

Can I use the dishwasher if I don't feel like hand-washing my tumbler?

Even if your mug is dishwasher-safe, proceed with caution as it isn't guaranteed to clean your cup as effectively. If you do decide to toss it in the dishwasher, follow the advice on Yeti's website: "Before it goes in the dishwasher, remove the rubber lid gasket to prevent any grime build up in the lid. Then throw it in the silverware basket." And when it's finished, don't forget to dry!

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