As of my last knowledge update in September 2021, WHMCS does not have a built-in feature to automatically prune or delete ticket attachments. However, you can manually remove attachments from tickets if needed.

Here's how you can manually remove attachments from a ticket in WHMCS:

1. Log into WHMCS: Access your WHMCS admin panel using your username and password.

2. Open the Ticket: Navigate to the specific ticket that contains the attachment you want to remove.

3. View Attachments: Within the ticket view, you should see a section for attachments. Click on the attachment you want to remove.

4. Remove Attachment: In the attachment view, look for an option to delete or remove the attachment. Click on it to confirm the removal.

Please note that manually removing attachments from tickets may be necessary if you need to free up space or if an attachment contains sensitive information that should no longer be accessible.

If you need automated pruning of ticket attachments, you may need to explore custom solutions or third-party plugins/add-ons that may have been developed after my last knowledge update. Always refer to the latest WHMCS documentation or community forums for the most up-to-date information on available features and extensions.