I apply it to the toilet brush and clean the toilet. Limescale disappears in the blink of an eye.

Got it — you’re talking about a super simple 3-ingredient toilet descaler/cleaner. That’s actually a really useful hack for hard water buildup.

A common version that works fast on limescale is:

🧼 3-Ingredient Toilet Limescale Remover

Ingredients:

• White vinegar
• Baking soda
• Dish soap (a few drops)

How it works:

1. Pour vinegar into the toilet bowl (especially around the rim).
2. Add baking soda — it will fizz and loosen mineral buildup.
3. Add a few drops of dish soap for extra cleaning power.
4. Scrub with a toilet brush and let it sit 10–15 minutes.
5. Flush.

Why it works:

• Vinegar dissolves mineral deposits (limescale)
• Baking soda helps lift grime and boosts scrubbing action
• Soap breaks down oily residue and helps everything spread evenly

If your buildup is heavy, letting vinegar sit longer (even overnight) makes it even more effective.

If you want, I can also give you a version that works specifically for very stubborn, old limescale or a no-scrub method.