[Plugin: Subscribe to Comments] Clear email list

I have reactivated the Subscribe to Comments plugion after a year. But I still have hundreds of people subscribed to old posts. Most of their emails are bouncing back into my spam folders.

Now I want to clear off all the users from the mailing list so they subscribe to fresh articles only. How can I empty the email list?

http://wordpress.org/extend/plugins/subscribe-to-comments/