No salt, no soda, no vinegar: the toilet will sparkle like a diamond – yellow stains will wash away themselves

In the evening, pour the entire pack of citric acid directly into the toilet bowl.
Let It Sit:
Allow the citric acid to work overnight. It will dissolve stains and mineral buildup while you sleep.
Flush the Toilet:
In the morning, simply flush the toilet. You’ll be amazed at how the yellow stains disappear without scrubbing.
Optional:
For stubborn stains, you can repeat the process as needed.
Benefits of Using Citric Acid