You can delete assigned and unassigned grid cards simultaneously using a CSV file. To delete grid cards in bulk, you need to a CSV file containing the list of assigned and unassigned grid cards.
The header row in your CSV file contains only one column with serialNumber as the value.
The following is a sample CSV file to help you get started:
serialNumber
1
2
3
4
Download a sample file: Bulk_sample_files/BulkDeleteGridCards.csv