Set the Plays ("Play Count" before iTunes v9.2) of the selected tracks to a user-entered number (they will all be set to the same number). If this number is 0 then the Last Played date of each track will be erased. (iTunes has the ability to "Reset Plays" to 0 from a track's contextual menu.)
Also see Add or Subtract Play Count and New Last Played Date.
Apple Music users should beware of a potential bug.
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Applet assists with swapping, copying, appending data between track tags
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Batch-change the Album Rating for the albums of selected tracks
downloaded 22m 24s ago
Renumber order of selected tracks
downloaded 22m 40s ago
Sort purchased tracks into discrete playlists by name or Apple ID
downloaded 27m 5s ago
Export album-artist pairs to tabbed file
downloaded 31m 35s ago
Use tag data to formulate new file name for selected tracks' files