Ok, I know not many of you are following this blog, but it would be great if someone could give an answer to this. So as you all know, you can farm any resource over vault level by sending carts or wagons alone, provided the enemy does not defend.
To farm gold however, you need to send some attack troops along with your wagons or carts, to be able to also take home gold. They need to ‘breach’ the wall and defeat the defending troops, even if, in actuality, no wall troops are present. So yesterday, I noticed I was running out of gold and farmed some of my close-by neighbors.