CLEANING A CLEAN
  1. attempting to clean up or deal with something that has already been cleaned up or dealt with or that wasn't troublesome to the person in the first place. (Scn AD)
  2. there is nothing there yet the auditor tries to get it and the pc ARC breaks. This is cleaning a clean with an E-meter. (HCO PL 16 Apr 65)
  3. this is the same as asking a pc for something that isn't there and develops a "withhold of nothing." (HCOB 13 Apr 64, Scn VI Part One Tone Arm Action)


Technical Dictionary