A method is provided for accelerating the drying of a cargo box (18) of a refrigerated truck (12), trailer (16), or container following a wash out. In an aspect, the method includes circulating air from the cargo box (18) through an evaporator (30) of the refrigerant unit (20) and back to the cargo box (18); and operating the refrigerant unit (20) in alternating cycles of first heating the circulating air and then cooling the circulating air.