You can use the master content list to perform actions en masse. For example, you can mass archive multiple entries at once.
To perform a mass action:
Search for the entry type you're looking for.
Check the box next to each entry you'd like to perform the action on. To select all entries at once, check the box next to the name of the farthest left column.
From the resulting option list, choose which status you'd like to apply (Unpublish, Delete, Archive, or Duplicate).
Your selection will be applied. A success message will be shown at the bottom of the screen when finished.