Home heating systems generally burn a variety of fuel sources, such as heating oil, gas, propane, and wood logs. Throughout the years and depending on weather and wind conditions, these elements create and build up different types of residues and soot. When these materials come in contact with water and moisture, they bond much more easily to any surface they land on. Unappealing chimney soot stains then form on the chimney, in which are sometimes irritating in appearance. Similar to the cleaning of a household oven, different techniques are used to remove the stains, such as brushing or applying chemicals and acids.