Gutters and downspouts are usually the first areas to show the discoloration on the home. Metals, the types of material that the majority of gutters are made of, carry a positive electrical charge. Any negatively charged particles in the air are attracted to the positive charge of the metal (opposites attract!), and the particles form an electric bond with the gutter called Electrostatic Bonding. Impossible to remove with normal household cleaners, it requires specialized cleansers and process specifically designed to break this electrostatic bond.