huge netbios traffic - after print server removal, next part

After print server removal (guys responsible of print servers) every workstation is trying to find print server which is unavailable. We have still wins servers but addresses are removed from wins and dns servers. So every 30 seconds every of 20k workstations is trying to find names at first by querrying wins, later by broadcasts. Finally network traffic from this source is huge. I must try to remove registry entries for missing print servers.