An automated sprayer for spraying the walls of a shower enclosure with a liquid cleanser dispenses the cleanser using a pump and rotatable spray head. A motor drives the pump and rotates the spray head. The sprayer has a showerhead mountable housing with a hanger. The housing supports a bottle of cleanser in an inverted fashion. Cleanser is delivered from the bottle through a cleanser conduit in the piercing post into a well of the housing. The bottle is vented from the well through an air vent path in the piercing post or from a well vent outlet through the air vent path in the piercing post. An outlet valve in the well permits outflow of cleanser from the well. Various bottle caps and bottle closures are also provided to improve venting and/or limit cleanser leakage from the bottle when the bottle is installed in the housing.