On her TikTok channel, self-proclaimed home expert Neat Caroline revealed how to eliminate unsightly underarm stains. "Make your white T-shirts bright again," she began in her tutorial video. "Because those armpit stains have to go."

Showcasing two of her "favourite" white T-shirts that underarm stains have ruined, Caroline said they also look fairly "dull". Grabbing a large bowl, "the largest one you have", Caroline puts the T-shirt inside and adds "one full scoop of oxygen bleach". She captioned the video, explaining that "oxygen bleach is a lot less harsh than chlorine bleach and it's colour-safe".

What is oxygen bleach?

Caroline said that oxygen bleach is "also known as Oxiclean" and that lots of other brands have oxygen bleach in them.

Examples in the UK could include Ecover Laundry Bleach, Vanish Gold Oxi Action Chlorine Free Stain Remover Powder, and Sodasan Oxygen Bleach.

Once the T-shirts and a scoop of oxygen bleach have been added to the bowl, it's time to add piping hot water from the kettle.

This leads to a "chemical reaction" that will effectively remove the stains from the T-shirts.

In order to make sure the cleaning solution works, you need to ensure the T-shirts are completely submerged in the oxygen bleach and hot water mixture.

"Then go about your day," Caroline advises, as it can take up to six hours for the oxygen bleach to break down the stains.

This is why it would be a good idea to begin this process before work, for example, so that by the time you've finished, you can move on to the next stage of the process.

Caroline said: "Then you're going to toss these in the wash with your other white clothes, your detergent, and a little bit more of the oxygen bleach."

Once washed and dried, there should be no more stains on the white T-shirts, and they should be looking brighter and whiter.

Admiring her own T-shirts, Caroline said: "They are looking super bright again and, importantly, no more pit stains."

In the comment section, fans flocked to sing Caroline's praises as the laundry hack had worked for them too.

One fan said: "I've tried this and had great luck with it." Although, another cautioned: "People, be careful. I just did this a few minutes ago; it makes a very strong odour! I had to open all my windows."