Ok so go to Field of the Dead in Epic mode.
Farm the bosses in the Haunted Forest = 30 silver + blue level 40-50 set drop.
On Fury EU these spots are highly camped by all the big guilds.
I suggest going there early morning or very late evening. If you're alone you can kill a boss about every 2minutes.
That's 30 bosses. That's 30x30 silver = 9 gold per hour.