Abstract: A device for washing and drying the inside tank portion of a tanker truck. The device is adaptable for fitting into a manway located in the tank and comprises a cone-shaped base which fits into a plugs the manway. A washing medium tube passes through the base in an axial direction and extends above and below the base. A drying medium tube also passes through the base in an axial direction and extends above the top of the base and terminates near the bottom of the base. A cone-shaped deflector is located below the bottom of the base and deflects drying medium throughout the entire inside portion of the tank. The device further comprises vent tubes which pass through the base in an axial direction and provides sufficient ventilation of the tank while maintaining a pressure greater than atmospheric in the tank. The positive pressure in the tank allows hoses connected to the tank to be cleaned and dried in an efficient manner.