A couple of things you could try:
Fill the empty case with crumpled newspaper (works in fridges that have been in storage)
Fill with a fullers earth based cat litter.
The outer part of the case seems to be fabric covered? If so, sprinkle with ordinary soda crystals, (which these days are more like powder) leave for a couple of days and vacuum off.
Good luck!
Michael Shellenberger: WPATH - 'Possibly the worst medical scandal in history'