How do I clear recently watched programs
If you watch until the very end, they will usually be removed from the Recently Watched row. I've shared the feedback with the technical team that there should be a method to manually remove programs (for privacy reasons).
select the show and hit info button. navigate to 'marked as unwatched'.
That isn't an option in the XFINITY TV app or website - only on the X1 set-top box - but will work if you have access to a television.