Carpet protector is applied to carpet fibers to give them added protection from stains and soils. The science of modern carpet protectors is that they reduce the surface energy of the carpet fiber and act like non-stick coatings on a cooking utensil. Soil, oil, and water all slip off the fiber. Many carpets are pretreated with protector at the mill, and may also be treated with a dye-blocker to further enhance the carpet’s stain resistance.