Castor oil is a natural emollient that penetrates the surface layers of the skin making it softer and more pliable. The effects of externally applied castor oil can be enhanced through the use of a "castor oil pack"- a piece of wool soaked in oil and applied to the body. Use of a pack allows the greatest penetration in a specific area of the body. The application of heat further increases this penetration, allowing the oil to better impart its natural qualities to the body.