Coca-Cola is an unlikely, but effective, way to unclog a toilet. A 2-liter bottle of Coca-Cola poured directly into the toilet should sit for at least 2 to 3 hours before flushing. The coke can sit for as long as overnight, especially for stubborn clogs.
Coca-Cola soda contains phosphoric acid, which helps break down agents that are clogging the toilet. This phosphoric acid is also helpful in removing stains in a toilet. This little-known remedy to unclog a toilet can be tried before calling in a professional plumber, but it primarily works on simple clogs and not on major obstructions.