EXPDATE and DAYS is specified on the print file level using Change Printer File (CHGPRTF), Create Printer File (CRTPRTF), Change Spooled File Attributes (CHGSPLFA), or Override with Printer File (OVRPRTF). You would then run DLTEXPSPLF periodically to clean up any expired spool files in the specified auxiliary storage pool group (ASPGRP).
For automation purposes, you could use the job scheduler function of i5/OS to run the DLTEXPSPLF command. An example of doing this can be found in the help text for DLTEXPSPLF.
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