Acidic solutions, such as those containing hydrochloric acid, phosphoric acid, or citric acid, are designed to break down the tough residues that a basic toilet cleaning product may struggle with.

Commercial cleaners tend to use hazardous substances such as hydrochloric acid ... The acid of my choice is citric acid." Why pick citric acid to banish toilet limescale? Thanks to its acidic ...

Zep, Lime-A-Way Toilet Bowl Cleaner and a cleaner marketed by Kohler, a toilet manufacturer, are up to 10 percent hydrochloric acid, also known as muriatic acid. Other cleaners use different acids.