Short answer
Yes. You can select multiple conversations in the History screen and delete them all at once.
Full explanation
AskTuring allows bulk deletion so you can quickly remove conversations you no longer need. To delete multiple conversations at once:
Go to the History screen from the left-hand menu.
Check the box next to each conversation you want to delete.
Click Delete at the bottom of the screen.
Confirm the deletion when prompted.
Once deleted, these conversations cannot be recovered, so double-check your selection before confirming.
Tips
Use bulk delete to quickly clean up old or irrelevant conversations.
If you may need a conversation later, download it before deleting.