Farming Runecloth guide WoW 2.4.3 (description)
Step 1: make a warlock and level it to 70. Gear score doesn't matter.
Step 2: go to hearthglen with a voidwalker. Make it aggro mobs at the 4 hotspots of mobs shown: the lumbermill, the blacksmith, the tunnel of the mine, and the pit of the mine.
Step 3: spam exactly 3 SoC's on 3 different mobs (best picked with Tab key) and finish them off with Hellfire before they run away.
Done. Farm runecloth.
--there is one difficult mob that you must kill first before you farm the mine. Foreman Jerris. He will kick your ass if you don't single him out. Deal with him first, or you will wipe. He takes a long time to respawn, so you should only have to kill him once per session.