Let’s start by defining the difference between a spot and a stain. A spot is any foreign material (soil, liquid, etc.) that is removable by standard cleaning methods. This means that the foreign material is on or around the carpet fiber. A stain is foreign material (soil, liquid, etc.) on a carpet that is not usually removable by standard cleaning methods. This means that the foreign material has penetrated, or soaked into, the fiber causing permanent damage or changing the fiber itself. Some stains may be very difficult or even impossible to remove.