How to delete all Notifications at once?

I am one of those people who is OCD about keeping an organized and clean inbox. I cannot stand to have thousands of read messages in there. Once I read them and deal with them, I want them gone.

On a recent video I got close to 2K comments. It has been overwhelming. I normally respond to ever single comment, and I eventually will, but I may take some time. My issue is with BELL Notifications. I have 20 thousand of them and I can find no way to clean them out. They never go away even after you reply to the comment. The only way I can find is to delte them one by one. Is there a way to delte them all at once? I only want to see new notifications as they come in, not stuf from days or weeks ago.