Ability to read and write at a level appropriate to the duties of the position; follow verbal and written instructions; safely operate and care for custodial equipment and supplies; observe safety requirements and maintain safe work practices; use custodial work-order systems and two-way radios; establish and maintain cooperative working relationships; and perform work requiring regular physical activity. Essential Functions : The incumbent sweeps, scrubs, mops, waxes, and polishes floors; cleans classrooms, laboratories, shops, lavatories, locker rooms, blackboards, windows, Venetian blinds, replenish lavatory supplies, empties wastebaskets, and removes trash, replaces lamps and light fixtures, unlocks and locks doors and windows.