We appreciate that you may have been part of yap groups which continued being active while you haven't been on Yapster, it is likely to mean you don't need to go into each yap group and read everything.
Below shows you how to clear all unread badges.
Click on the Settings Cog in the left hand corner of your screen and click on Notification Preferences.
Scroll down to Clear all unread badges and click.
End result: clears all your unread badges!