Found this yesterday while progressing through NM... I honestly dont know how well it works in hell/normal but it worked pretty damn well in nm. Went from 32 to 38 really quick. (Usually an enlight shrine outside)
Trailing the Coven
Explore the manor
You may have to actually be on the "Explore the manor" quest to actually continue farming this.
Trailing the Coven
Explore the manor
You may have to actually be on the "Explore the manor" quest to actually continue farming this.
After you clear, you just repeat the process.
Here's a video.
http://www.youtube.com/watch?feature=player_embedded&v=QP2ZMCgkXfs