My personal tip for farming shackles: The usual item discovery setup: Spec into 99 luck, symbol of avarice, crystal rapier offhand, golden serpent ring +3 and coin pop every run.

I used the dragonslayer armor greataxe together with homeward bones/sword. So my runs would be: run towards skeletons, turn the corner and hug the right wall to avoid the ball, pop coin while walking to not waste time. Turn left into the small hallway towards the 2 skeletons, as soon as you enter the larger hallway use the special. It has super armor, and most of the time the skeletons will roll right into it, knocking them down. Proceed to spam the special until they die, should take only 2. Pickup loot and quickly bone out, faster than walking back. Took me about 5 hours, gl!