Whitewash is a paint-like fluid used as a cheap protective layer on exterior structures.
It's been used since humans learned how to use limestone . Quicklime is the main ingredient, along with water , salt and a glue or adhesive to provide some permanence. Ingredients used on the American frontier included flour , molasses , soap , sand and various calcium compounds. Powdered fish glue was commonly used as the adhesive additive, and for special purposes other ingredients like zinc , potash , milk and pigments were added for fireproofing and coloring. When used indoors, whitewash uses different ingredients and is called Calcimine or Kalsomine .