But it turns out he has another use for the lemons.
He revealed that he cuts up two lemons, puts them in the kettle, fills it up with water and boils it. After it's boiled, he waits for it to settle and turns it on again before rinsing it out.
"The black bits on the inside of the kettle is from the water due to the hardness of it," he explained.
"Hardness in drinking water is mainly the result of the presence of large amounts of two minerals - calcium and magnesium."
Hard water can also cause limescale to form on hot water pipes and fittings. It's a chalky deposit consisting mainly of calcium carbonate. But limescale renders kettles useless, meaning they'll need to be replaced.
Nat shared his expert advice on a Facebook group called Markdown Addicts Australia, where thousands thanked him for sharing the simple trick.
Others shared a few methods of their own.
You can use lemons to clean your kettle with this simple hack. Photos / Markdown Addicts Australia, Facebook
"This is a great tip," one commented. "I was just about to clean my kettle with a brush and some soap, but I'm going to try this instead!"
Another wrote, "Leftover lemonade works just as well if you don't have lemons on you, and plus, it smells delightful.'
She added, "I just boil lemonade with water, let it sit a few minutes, and repeat. Then I just rinse it out and it's sparkling clean.
"I've done this for years and don't have to worry too much about making sure it's totally rinsed - as lemon tea tastes better than vinegar or chemicals!"
Many also shared there's another household item you can use to clean your kettle - but warned against a common mistake you can make with it.
"I use a dash of vinegar when I don't have any lemons or lemonade on hand and also works fine," one man shared.
"But remember to empty the vinegar water and boil the kettle again before tipping it out completely.
