1. As a backup measure, export the records you wish to delete, being sure to select all fields. (See Export Data.) Save an extra copy of the generated CSV file.
2. Next, export the records you wish to delete, this time using only the record ID as the desired criterion.
3. Launch the Data Loader and follow the delete or hard delete wizard. Map only the ID column. See Insert, Update, or Delete Data Using Data Loader.
4. After the operation, review your success and error log files. See Review Data Loader Output Files.