For macOS 10.10 and later only. This script will "refresh" the selected user-created Smart Playlists by removing the tracks they contain (if possible*) which then obliges them to dynamically repopulate, ostensibly with different tracks.
*Note that tracks cannot be removed from a Smart Playlist which already contains every track of the library meeting its criteria--it would just repopulate with the same tracks. Smart Playlists with the "Limit to" and "Live updating" criteria in use are more likely to be "refreshable".
Also see Refresh Selected Smart Playlist, which works with a single Smart Playlist selected in iTunes.
Click "Refresh" to re-populate the selected Smart Playlists.
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