Related Questions:
How can I do a batch delete of Menu Items?
How can I see a list of Menu Items that aren't on Invoices?
Answer:
It is not possible to mass delete Menu Items in Event Temple. Deleting Menu Items must be done from within the Booking that owns them.
How to see Menu Items that don't belong to an Invoice
To see a list of Menu Items that aren't on Invoices you can use the Menu Item List (Booking) Report:
Click on Reports in the left hand menu
Click on Menu Item List (Booking)
Click + Add Filter
Click the dropdown and select the option Does Not Belong To
Click in the Search bar that appears and select Invoice
Click Apply
Optional: Add additional filters to further tailor the list
Once you have the list you are looking for, you will be able to click on the name of the Booking associated with the Menu Item in the list and you can then delete the appropriate Menu Items from the Booking Summary you are brought to.