Turns out we're all washing our water bottles wrong.

Walking out of the house without a reusable water bottle (looking at you, Stanley Quencher Cup) is like forgetting your phone. In other words, it's a BIG deal. HUGE.

But while we've become obsessed with drinking out of our emotional support water bottles, it's time we all become equally (or even more) obsessed with cleaning it.

Yep, apparently, we've been doing it all wrong and our favourite hydration accessory could actually be making us sick…

Watch: Mia Freedman sits down with Lisa Millar and Leigh Sales to talk about friendship and journalism.

According to a viral TikTok video by a woman named Skylar, there's one part of the Stanley Cup that's a hidden breeding ground for mould: under the lid's lip.

In the video that has racked up over 9.7 million views, Skylar squeezes the small compartment lid, revealing black specks peppered across the top.

"I literally have mould," she screamed. "This is so gross."

@skysayingthings

NOT THE MOLD 😭😭😭😭

♬ original sound - SKYLAR ✨🩷

And it's not just the lid. Another TikToker, Nicole Kramer, discovered mould inside the body of her cup.

"Never underestimate how often you need to clean your Stanley cup," Kramer said at the start of the video, which showcased spores inside the vessel. "I've had the worst sore throat. No idea why. Look inside my cup this morning… you don't even want to see the straw."

@nicolekramer_

I use my Stanley on a daily basis and it’s so easy to forget the last time you washed it when you never stop using it. Im still gagging

♬ original sound - NICOLE KRAMER

Ahhhh freaked out? Same.

How to wash your Stanley Quencher Cup properly to avoid mould growth.

The good news is that it's not hard to keep your Stanley Cup (or any water bottle) from becoming a mould nursery.

Firstly, you must wash it inside and out after every use. This ensures that any lingering moisture or residue that can promote mould growth is thoroughly removed.

The easiest way to do this is by separating all the different parts and popping them in the dishwasher. Most bottles are dishwasher-safe these days, but just double-check the base of yours to confirm.

If you prefer handwashing, take apart all components and clean them with warm water, mild detergent, and a kitchen sponge. Apply a bit of elbow grease to tackle stubborn spots, rinse thoroughly, and dry the parts with a clean cloth or let them air dry. If your bottle has a straw, using a narrow brush will help clean the inside effectively (here's an affordable pack of two you can purchase on Amazon).

If you want to go the extra mile and give your Stanley Cup a deep clean, Kyle Casteel, Senior Hydration Product Manager at Stanley (what a job title!) told People, "If your product needs a deeper clean, use a mixture of one-part baking soda and one-part warm water, and soak for up to an hour. Then clean with mild detergent once the solution is rinsed out."

This method helps break down any stubborn residue and ensures your bottle stays fresh and safe to use.

If you're still unsure about the process, TikToker Clara Jones offers a detailed, step-by-step guide to help you keep your bottle spick-and-span.

@theclarajones

no judgment zone here #stanley #fyp

♬ all my ghosts - Lizzy McAlpine

Feature image: TikTok @theclarajones/skysayingthings.

How do you keep your bottle clean? Share your thoughts with us in the comments section below.