A stain is to discolor or soil cotton fabrics. A saponin is natural occurring oily glycoside foam that forms freely when shaken with water. Soap is made from animal and vegetable fats, oils, and greases. Cotton is a natural vegetable fiber also used largely because of the fibers. The fibers in the cotton make it so that when a stain gets on there it soaks in.
Detergent is the salt of sulfonic acid, which then forms sulfonate ions in water.
How To Clean Everything. Washing Agents -for washable fabrics.