A method cleans surfaces in an internal volume of an aircraft component through which a medium flows. The method includes: connecting the internal volume to be cleaned to a steam generator; generating a cleaning steam having a predetermined vapour pressure and temperature by the steam generator; applying the cleaning steam to the surfaces to be cleaned in the internal volume; maintaining the vapour pressure and the temperature within the internal volume for the duration of a predetermined condensation time; generating a pressure drop in the internal volume of the aircraft component, in order to vaporise the portion of the cleaning steam that condensed during the condensation time; and removing the cleaning steam from the internal volume via a discharge device.