An Expert Explains Why You Shouldn’t Put Your Stanley Mug in the Dishwasher

The Stanley cup went from blue collar classic to viral hydration sensation in a matter of months. There’s plenty of reasons to love the travel mug including a built-in straw that amounts to less water dribbling down your chin and an air-tight cap that keeps spills from happening. All those features mean that the Stanley has a few nooks and crannies to clean. Forgoing a regular deep-clean could lead to a buildup of grime and mold — two things you definitely don’t want in your water. 

For the best way to clean a Stanley travel mug, we turned to an expert on the matter. 

“Cleaning Stanley cups regularly is essential to keep them clean and safe to drink from,” says Sabrina Tretyakova, of Fotador, a cleaning technician certified through the International Sanitary Supply Association. “Factors that influence the growth of bacteria and mold on Stanley cups include moisture, the presence of nutrients from the beverages themselves, and lack of regular cleaning,” she says.

Parts of your Stanley cup that need cleaning

There’s more than meets the eye when it comes to the various parts of your Stanley cup or insulated mug, and it’s not enough even if you’re regularly washing the inside of the cup and the sipping mechanism. Here are several problematic areas that Tretyakova identified:

Under the spout protector

Depending on what type of drinking vessel you have, this is easy to miss as it’s not a piece that your mouth directly touches, though it’s frequently coming in contact with the spout that your mouth touches, allowing bacteria and mold to accumulate.

Straw and lid

“These parts are prime locations for bacterial growth because they come into direct contact with your mouth and the beverages,” says Tretyakova. “The bacteria can be oral flora, which lurks in your mouth and gets transferred to the cup.” (If the words “oral flora” didn’t send you directly to the kitchen sink for immediate deep cleaning, I don’t know what will.)

Rubber seals

Certain models have rubber seals on the lids to help keep them closed tightly, but this is another area that Tretyakova identified as being troublesome when it comes to hygiene. “The areas under the seals are vulnerable to mold contamination if not cleaned properly,” she says. “Usually, this area gets infested with black mold, also known as Stachybotrys chartarum.” (Choose your own adventure: Which is more scary, oral flora or black mold?)

How to clean your Stanley cup or insulated mug

Here are Tretyakova’s recommended best practices when it comes to cleaning and maintaining your insulated mug.

1. Regular rinsing

“Rinse the mug and the lid under hot water shortly after drinking the beverage,” says Tretyakova. “It helps remove any residue that could potentially harbor bacteria.” This isn’t in place of actually cleaning the mug, but is a good habit to get into, especially if you’re in a work or public environment and aren’t immediately able to attend to it.

2. Thorough cleaning

First, disassemble your Stanley Cup or other insulated mug completely so that there are no hidden areas that may harbor moisture and can encourage bacterial growth. Tretyakova recommends mild dish soap and warm water to soak the removable parts of the cup for 15 minutes. (Throwing the cup in there itself is also a good idea while you’re at it.)

Scrub the parts with a clean toothbrush or bottle brush, and finish by rinsing the parts with warm water. You can hand dry any parts that are easily accessible with a clean towel, but other parts such as straws will have to air dry.

3. Avoid the dishwasher

The Stanley cup and some other insulated mugs may be dishwasher safe, but using the dishwasher isn’t necessarily recommended for the best cleaning. “The dishwasher may not reach all the nooks and crannies on the lid of your mug,” says Tretyakova, who advises regular hand washing for the best outcome. 

4. Periodic deep cleaning

Tretyakova recommends periodic deep cleaning in addition to daily cleaning, which can be done with distilled white vinegar and baking soda.

Read more: These Pantry Staples Will Melt Ugly Cookware Stains in Minutes

Steam clean for additional peace of mind 

For those about to swear off insulated mugs forever, take note: There is more that can be done to keep your cup clean and sanitized. Similar to bottle cleaners that are sold as baby products, steam sanitizers are available for a multitude of home uses, of which insulated mugs are prime candidates.

“Rubber sealing rings and slide openings of lids can trap moisture, even after they have been washed, and straws are challenging due to their length and shape,” says Nicole Backus, a product manager for Clorox Home Appliances. Where moisture is the problem, moisture in the form of steam can also be the solution.

“Sanitizing with steam is especially helpful, as steam can penetrate cracks and crevices where scrub brushes, soap and water cannot reach,” Backus says. “Sanitizing even clean parts of your insulated mug keeps bacteria from growing on surfaces of the cup, inside and out, top to bottom.” 

Sanitizing should be done after washing, not in place of, but for extra peace of mind, you can get a sanitizer for home use such as the Clorox 2-Tier Steam Sanitizer for as little as $50. (You spent that on the Stanley already, so consider it insurance.)