managed Clients and printing list

Hi,
we have discovered the following problem.
When a user logs in on a machine that other users have used before, the new user sees all the printers that were assigned to the users before.
They are NOT displayed in the Systemsettings, but ARE displayed in the printing list thats used while printing.
It seems that CUPS only adds printers and does not care if the user should see them or not.
Deleting them in CUPS and relogging does the job, but this is not a clean way to handle this.
Can anyone help?
regards

Oliver