Items placed in the trash are deleted permanently when AerWave detects that they are no longer in use.  For example, when a content object is no longer referenced by any Program or Playlist in any domain, it will be eligible for automatic deletion if it's placed in the trash.  The deletion may take up to 10 minutes to occur once all references are gone.  It is not possible to force a content item to be permanently deleted if it is currently in use by a Program or Playlist.