We typically see two types of grout stains that are classified as either “organic” or “inorganic.” Organic stains include food stains, such as fats, grease, proteins and carbohydrates. Organic stains also can be caused by living matter, such as mold, yeast and bacteria. Petroleum stains, including motor oil, grease and cooking oil, are also organic. Alkaline cleaners, such as our UltraCare Heavy-Duty Stone, Tile & Grout Cleaner, work well on organic stains.
Inorganic stains include rust, scale, hard water deposits, and minerals such as sand, silt and efflorescence. A low-PH acidic cleaner, such as our UltraCare Sulfamic Acid Crystals, typically works well on these types of stains.