In order to recover the resources (cleaning agent, heat) contained in the cleaning agent vapors suctioned off a cleaning system for cleaning industrially produced components, it is proposed to guide the suctioned-off waste air ({dot over (V)}ab) in a recovery device (5) through a heat register (9) of a refrigeration device (6) and thereby to heat it substantially to the temperature of the waste air ({dot over (V)}ab), and to supply the waste air ({dot over (V)}ab) heated and dried in this manner to the cleaning chamber (2) in the region of a bulkhead door (16) as preheated dried supply air ({dot over (V)}zu).