One method to delete multiple pages (or messages) at a time is to find all pages before or after a specific date, then delete all of the pages you found.
To do this, follow these steps:
1) Open the Pager application by tapping the Extras drawer, then tapping the Pager icon.
2) Tap Find to display the Find slip.
3) Tap Look for, then tap either "dates before" or "dates after". Since each page is time and date stamped, this will display a list of pages that were received either before or after the date you entered in the Find slip.
4) Tap the overview dot between the arrows at the bottom of the screen to display the selected list of pages.
5) Tap the Envelope icon at the bottom of the list, then tap Delete. All of the pages in the list will be deleted.