On the desktop site (Not tapatalk) click on "settings" up under your user name in the upper right hand corner.
On the left hand side of the next screen, there boxes for different tasks. One is titled "My Subscriptions" Click on "subscriptions" right underneath it.
All of your subscribed threads will be displayed. Scroll to the bottom of the list and click the button labeled "empty current folder"
Next screen will ask if you are sure.....................press yes!
Or, simply click on one of the two unsubscribe links at the bottom of your email!