3Com PalmPilot - Manual (Page 41)

Chapter 1: Mail page 37
you can purge the contents of your Deleted folder. Messages that
have been purged will still be deleted from your desktop e-mail
application during the next HotSync operation.
To purge the contents of the Deleted folder:
1. Tap the Menu button to display menu options. From the
Options menu, tap the Purge Deleted command.
2. Your PalmPilot will display a Purge Deleted Messages alert.
Tap the Yes button to confirm that you want to immediately
purge the contents of the Deleted folder. All messages from
the folder will be deleted.
Note: Messages that have been purged cannot be restored.