The easiest way is to generate some TicketSQL using the built in RT Query Builder to find just the tickets you want to delete. You’ll need to do this because we don’t know what queues, etc you have in your RT installation. Check that query you build finds just the tickets you want gone - no more, no less. Check and double check this before proceeding.
Once you’re absolutely sure that the Query Builder query you have made finds the tickets you want to get rid of, use the command:
rt-shredder --sqldump unshred.sql --plugin 'Tickets=query,<insert your SQL here>"'
<insert your SQL here> with the TicketSQL shown in the Query Builder advance view. The
--sqldump option is a useful safety net. It generates a file called
unshred.sql that you can squirt back into the database to put things back as they were if you do find that, despite your careful checking of the SQL results before running the
rt-shredder command, you’ve nuked some tickets you shouldn’t have.
Of course if you’re uncomfortable doing this you can always contact those terribly nice Best Practical folk to see about paying for support and help.