How to delete multiple Grade Center columns with one process.
The Grade Center does not provide an option to delete multiple Grade Columns. Instead, columns must be deleted one at a time. The “Batch Delete Grade Columns‟ tool enables you to quickly select and delete multiple Grade Columns.
Note: As with the Grade Center, the tool does not allow you to delete any columns which are associated with gradable items (assignments, tests, etc.) or the column which is marked as “External Grade”