1. Pour it in.
2. Let it sit 5-10 minutes.
3. Give your bowl a wipe.
4. Shiny Clean.

Buckin Bowl Clener works.

A detergent-thickened 9.5% hydrochloric acid toilet bowl cleaner that effectively cleans, deodorizes and disinfects porcelain, ceramic and vitreous china toilet bowls and urinals. Superb cleaning action removes hard water films and rust stains.

Why does Buckin' Bowl Cleaner Work? Take it from Wade:

Hydrochloric acid (HCl), the primary active ingredient in Buckin' Bowl Cleaner, is a very strong acid. On porcelain surfaces, HCl dissolves tough stains like rust, mineral deposits, or limescale (from hard water). Porcelain doesn’t react much with acids, so the HCl can do its cleaning magic without eating away at the material.

Do NOT use on stainless steel. Buckin Bowl Cleaner works too well for it's own good!

Stainless steel is “stainless” because it forms a super thin, invisible layer of chromium oxide that protects it from rust. When you splash HCl on stainless steel, the acid destroys that protective layer. Once the chromium oxide is gone, the steel underneath is exposed and starts corroding fast. Instead of shiny, smooth stainless, you get rust.