The Windows 2000 Printer Pruner automatically scavenges orphaned printer que throughout the enterprise.
This keeps the Active Directory list of printers to choose from current.
For Printer Pruner to function, every site in the enterprise must have a domain controller running the spooler.
See Microsoft Knowledge Base articles:
Q246906 - Printer Pruner May Prune All the Print Queue Objects on Its Site.
Q246174 - Printer Pruner May Not Remove Printer Queue Objects from Active Directory.