can quickly turn brown where the soles of the feet would be; and, most of the time, washing detergent doesn't lift the stains.

When Amy Chu couldn't resolve the unsightly marks on her daughter's once white socks, she sought out advice on the Army Cleaning Tips Facebook page.

Ms Chu inquired: "Does anyone know how to get dirty marks out of white socks?

The community found on the group quickly shared their go-to method to

One member suggested: "Soak in soda crystals for half an hour before popping on a hot white wash. Miracle worker!"

Echoing this sentiment, somebody else advised: "Soda crystals and a scoop of detergent soak in hot water and then put amongst wash."

Another member similarly endorsed the approach, adding: "Soak with soda crystals for 30 minutes then put in the washing machine. They'll come out dazzling."

One more agreed: "Leave to soak in soda crystals. Then add them to a white wash and add a big scoop of soda crystals. All natural and work wonders."

Another commentator exclaimed: "Soda crystals in a saucepan is game-changing. Just boil it on the cooker like they used to years ago. It works."

While someone else shared her method: "Big saucepan with soda crystals and boiling water, then just let them have a simmer for about half an hour and then put them on a white wash. Always works for me."

While not a bleaching agent, soda crystals have evidently gained a cult following based on its stain-lifting powers. Soda crystals can be found at the likes of supermarkets and , for as little as £2.

Another recommended product was Napisan, which is also available at for £4.50 or 's for £5.

Other suggested , claiming the product is "fantastic" and is "better than any [other] products" to whiten socks.