My jobs stay in the queue after printing.

It's a known bug, and looks fixed in 2.5.
There's also a number of lpsched patches out for
Solaris: 101025-xx (2.2), 101317-xx (2.3),
101959-xx (2.4) and 101960-xx (2.4/x86).
Make sure you install those.

Regardless of what other patches you apply, if you have a printer
connected to your system running Solaris 2.4 or later, and if that
printer uses NeWSprint software, you must apply patch 102113-xx.
This patch is included on the Solaris CD in 2.4 and later
releases. This patch is also required if you are running Solaris
2.3 with kernel jumbo patch 101318-55 or later. Note that this is
a NeWSprint patch, not a Solaris patch, and hence it will never be
integrated into any Solaris release.

"lpstat" on the clients on a regular basis, for some reason
this clears the old files from the queue directories.

ASGAUR