After a long day of traveling, you finally get home after being away for a while, and head straight to the bathroom and your own familiar toilet. But instead of the shiny white bowl you left behind, you find a toilet full of brown streaks and a ring. This is (probably) because you live in the 85% of the United States with hard water.

If you’re only going to be away for a short while, your usual cleaning solution and a quick spin of your toilet brush should remove any fresh stains. But stains that have been there for weeks (or months, or years) will be much more stubborn. Here’s how to rid your toilet of the worst limescale stains.

Hard water contains dissolved minerals such as calcium, magnesium and iron. When hard water dries on surfaces such as chrome faucets, it often leaves behind chalky white stains (which are technically mineral deposits).

That residue can also get into the dry parts of your toilet bowl, but if your toilet is white, you probably won’t see it. It’s much harder to ignore brown or rust-colored rings or stains, which are usually the result of iron or manganese compounds in your water.