When sodium bisulfate is mixed with water, a highly-corrosive acidic solution is produced, which dissolves accumulated minerals such as iron, magnesium and calcium from the bowl.
[2] Sani-Flush was introduced by the Hygienic Products Company of Chicago, Illinois in 1911 as a toilet bowl cleaner; since 1922 it had also been promoted[3] for flushing "rust, scale and sludge" from automobile radiators.
The primary direct competitor to Sani-Flush was Vanish, a brand of toilet cleaning crystals marketed in the US by Drackett, which was later acquired by the SC Johnson Company.
[8] On April 8, 1964 a Winn-Dixie food store in St. Petersburg, Florida was evacuated and eleven people hospitalized when a combination of these two incompatible products was used to clean a floor.
[9] Sani-Flush is mentioned several times in William S. Burroughs' novel Naked Lunch, where the product is used to "cut" (dilute) cocaine or where it is substituted for morphine by a pharmacist.