Carpet cleaners are designed for spot removal. It consists of a small box. The base of the box has rollers & brushes, connected by a belt or gears. There is also a container for dirt. The arrangement is such that when pushed along a floor, the rollers turn and force the brushes to rotate. The brushes sweep dirt and dust from the floor into the container. Some cleaner is filled with water & commercial cleaning solutions. It clean the carpets by injecting a cleaning solution into the pile, which is then sucked back into the machine with all the dirt and grime from the fibers.