Abstract: A method for preserving cavity spaces, particularly in an automobile chassis, is provided wherein wax is applied onto the inside walls of the cavity space to be preserved, being applied with application nozzles. The wax is heated and the heated and liquified wax is supplied under pressure to a pre-atomizer nozzle and is atomized by the latter. At the same time, compressed air is heated and is mixed in its heated condition to the jet of wax drops emerging from the pre-atomizer nozzle and relaxed. Finally, the hot mixture of wax drops and air is supplied to the application nozzle and the latter sprays it onto the walls of the cavity space to be preserved. An apparatus for the implementation of this method is composed of a heatable delivery line for the hot and liquified wax, of a pre-atomizer nozzle having a following discharge tube, of a compressed air delivery line having an air heater and of a nozzle tube having application nozzle apertures.