Some customers might be finding a second use for hotel room kettles.

hotel room kettle
Credit: Getty Images/Oktay Ortakcioglu

Boiling yourself a cup of tea can be a relaxing way to unwind in your hotel room, but you might want to think twice about using the kettle: Some customers may be using that kettle to clean their undergarments.

The action came to light after someone posted the following question on Twitter: “Real question: does anyone I know clean their underwear in a kettle when traveling?”

Similar rumored incidents of people using the kettles to boil their undergarments have also been spotted on Weibo, China’s Twitter-like online networking tool, with users saying they have heard accounts of people who supposedly use the kettles to clean their underwear.

Now, experts are warning against the danger of taking this type of action, with Dr. Heather Hendrickson, a senior lecturer in molecular biosciences at the Institute of Natural and Mathematical Sciences at Massey University in Auckland, explaining to Gizmodo just how alarming using the kettle for that purpose can be.

“It is super, super, super, gross,” she told Gizmodo.

While boiling will kill most of the bacterial pathogens in the water, or lower them to a level that won’t affect your health, it’s tough to know how long that water has been sitting in the kettle before the next person uses it, according to Hendrickson. She also mentioned that some types of bacteria are resistant to high temperatures, causing danger to someone’s health.

“There are simply too many unknowns and hotel kettles are not industrial strength cleaning facilities,” she said.

Unfortunately, kettles are not the only item you’ll want to think twice about using during your next hotel stay.

A recent study found that hotel hair dryers can be dirtier than sinks and toilets, since they’re often overlooked as an item that needs cleaning.