How to clean 'discuss_notifications' table after spamming

Hello

Due to grant access to 'guest' to create a discussion forum in EasyDiscuss (permission by default !), my site was spammed.
I delete the wrong rows in many discuss_xxx tables but I don't know how to clean the discuss_notifications.

This table is far too big (43422 rows !!, 9.8MB, etc.).
I would remove all the rows but I am not 100% sure there is no dependencies with other discuss_xxx tables.

My question is :
- can you check of I can remove all rows from discuss_notifications table ?
- if not, please provide me the SQL request to select the rows I have to delete.

Thanks
Henri