You can remove a series, which deletes the folder and all of its contents, from the Library. The individual assets, if copied from a stock folder, still exist in the Library.
To remove a custom series
The Library Manager displays.
A warning messages displays that you are about to permanently remove the series folder and all of its contents.
Notes: Removing a series is an unrecoverable action; you cannot undo it. The content may still be discoverable via search or browse if the asset(s) were contained in a different folder or hierarchy in the Library.