Solvent cleaning and degreasing is the process of using an organic solvent to remove unwanted grease, oils, and other organic films from surfaces. Cold cleaning is the simplest, least costly, and most common type of solvent cleaning. The solvent is usually applied at ambient temperature or is heated slightly. It is applied either by brush or by dipping the items to be cleaned in a solvent dip tank. The most common solvent applied for cold cleaning is known by the proprietary commercial names of Stoddard Solvent or Varsol. Vapor degreasing uses non-flammable, chlorinated hydrocarbons in a vapor phase to clean metallic and other suitable surfaces. The special apparatus that provides solvent vapor consists of a tank that is one-tenth full of solvent. The solvent is heated, usually by steam coils, to its boiling point, producing solvent-saturated vapor in the upper portion of the tank.