One of the active ingredients in Coca Cola is phosphoric acid. It has a pH of 2.8, (On a scale of 1 -14, with 1 being the most acidic, 7 being neutral, and 14 being very caustic). Pure phosporic acid can eat through metal, and disolve concrete, but it sure makes the coke taste good.

Rumors say that Coke distributors have used it over the years to clean the engines of their delivery trucks, and it also works to help scrub road grime from your windsheild. We can't acutally advise using Coke as a substitue for regular detergents, however there are some interesting ideas people have put forward over the years:

Pour a can of Coca-Cola into the toilet bowl. Let the "real thing" sit for one hour, then flush clean. The citric acid in Coke removes stains from vitreous china. It should work equally well for sinks and bath tubs. This is according to household-hints columnist MaryEllen.

Rub the bumper with a crumpled-up piece of Reynolds Wrap aluminum foil dipped in Coca-Cola.

Pour a can of Coca-Cola over the terminals to bubble away the corrosion. This is according to Heloise.

Applying a cloth soaked in Coca-Cola to the rusted bolt for several minutes.

Empty a can of Coke into a load of greasy clothes, add detergent, and run through a regular cycle. The Coca-Cola will help loosen grease stains.

(article taken from howtocleananything.com)