Heavy duty cleaners often move furniture, large containers of recycled materials and waste, and other objects, and operate large buffers and other weighty equipment. "Light" duty cleaners clean chalk boards, windows, shelves, desks, light fixtures, and ledges. Some duties, like using a vacuum cleaner, can be done by either "light" or "heavy" duty cleaners. Cleaners can clean offices, staircases, kitchens, bathrooms, hallways, sidewalks, elevators, escalators, and other areas. Cleaners can specialize in washing windows, or in cleaning carpets, hospitals, food processing plants, or construction sites. Cleaners who discover seriously damaged surfaces and equipment on their sites can notify specialists, like plumbers and carpenters, about the need for professional repairs.