Abstract: The invention is directed toward an apparatus and method for cleaning trailers of transport trucks, which makes use of an air supply of an air brake system within the transport truck. A portable cleaning apparatus is connected to the air brake system to allow a user to clean soiled surfaces in the interior of the trailer. One embodiment of the cleaning apparatus includes an air supply hose, a wand, and a liquid delivery system which may include a portable container containing liquid and a mixer for combining the air and liquid. As air flows through the compressed air supply line and out of the wand, the airflow siphons liquid from the portable container at the mixer.