It's possible to delete tickets in bulk in Teamleader Focus. Just follow the steps described in this article.
First of all, you need to have admin rights to be able to delete tickets in bulk.
Go to Shared inbox
Create a new segment or select an existing one
A button Actions appears on the right-hand side
Click on it and choose Delete
Confirm the action. Note that this action cannot be undone!
Click on Do now. Your tickets will be deleted.