Soil removal is quite a process that is more involved than adding soap or surfactant to water. One of the concerns in dealing with cleaning compounds is water hardness. Water is made “hard” by calcium, magnesium, iron and manganese metal ions. These metal ions interfere with the cleaning ability of detergents. The metal ions act like dirt and “tie up” the surfactants, making them unable to act on the surface we want to clean. A chelating agent combines itself with these disruptive metal ions in the water. The metal ions are surrounded by the claw-like chelating agent which alters the electronic charge of the metal ions from positive to negative (see diagram below.) This makes it impossible for the metal ions to be precipitated with the surfactants. As a result, chelated metal ions remain tied up in solution in a harmless state where they will not use up the surfactants.