Black or dark stains on the bottom and under the rim of the toilet are usually not ordinary dirt, but a hardened layer of water and urine deposits on which dirt, bacteria, and mold have accumulated. That’s why conventional scrubbing with a brush and soap doesn’t help.
To finally remove these stubborn deposits, there’s a reliable trick that combines the power of natural acids with the correct application.
Reliable trick: Citric acid and vinegar (leave overnight)
It’s important that the cleaning agent comes into direct contact with the deposits without being diluted with the water in the toilet bowl and is left to work for a sufficient amount of time.
Pumping water out of the bowl: The most important step.
Using an old cup, a large syringe, or a toilet brush (in up-and-down motions), push or pump as much water as possible out of the toilet bowl. If the limescale remains submerged, the cleaner will be diluted and lose its effectiveness.
Prepare the super solution: Within 5 minutes.
Dissolve 2 to 3 tablespoons of citric acid in 500 ml of warm vinegar. The warm vinegar helps the acid dissolve more easily and activates its cleaning power.
Treat stains: Leave to soak overnight.
Pour the solution into the toilet bowl. If there are also black stains under the rim, soak paper towels in the solution and press them firmly onto the affected areas under the rim. Ideally, leave to soak overnight (but at least 2 to 3 hours).
Mechanical cleaning: In the morning.
In the morning, remove the paper towels from under the rim (in the trash, not in the toilet to avoid blockages). The limescale will soften overnight. Take a toilet brush or an old sponge (wearing gloves) and simply scrub the stains. Then flush.
Other effective alternatives:
If you don’t have vinegar or citric acid on hand, you can try these tried-and-tested methods:
Laundry detergent: Put a cup of laundry detergent in an empty bowl and pour some hot (not boiling, to avoid damaging the ceramic) water over it. Laundry detergent contains water softeners and bleach, which effectively dissolve deposits. Let it soak for a few hours.
A mixture of baking soda and vinegar: If the stains protrude above the water’s surface, sprinkle them with baking soda and then spray them with vinegar from a spray bottle. It will foam up a lot—this reaction helps to mechanically loosen the dirt from the surface.
Pumice stone for toilets: If chemical cleaners don’t work, you can buy a special pumice stone with a handle for toilet cleaning at drugstores. It won’t scratch the ceramic but will remove mineral deposits.
Safety note: Acidic household cleaners (vinegar, citric acid) should never be mixed with chlorine-based products (e.g., classic Savo). The mixture causes a chemical reaction that releases chlorine gas, which is harmful to health and toxic.