Tam, you're the best !!!Click SETTINGS (at top of page).
It will open a window at your profile page.
The top box line will have: Subscribed Threads with New Posts: (0)
Click the button on the right that says: View All Subscribed Threads
You can edit your folders there to delete.
thread tools - upper right of the thread... and while we're at it ... why do you have to subscribe to a thread you started to get updates on it?