Windwool was introduced by the expansion Mist of Pandaria. Windwool is dropped by humanoids between the levels of 86 to 92. At level 90 head over to The Dread Wastes, south of Klaxxi’vess within the scar. Before farming for Windwool Cloth, get the buff Angel of Death to assist with DPS and Potion of Luck if possible to increase the drop rate of Windwool Cloths.
Starting from the red circle on the right in the map, find the Elite scorpion and other creeps amongst it. Slay the normal monsters with AoE skills if available and let Kil’ruk assist with the DPS. When the fight is over, it will take 60 seconds for Kil’ruk to be ready to assist again. During this time find some random creeps to slay before moving towards the second circle to find another Elite Scorpion and more mobs in the area. Execute the same as before, slay the normal creeps and Kil’ruk will descend from the sky to help you fight. When it is all over, move towards the third circle and kill the Elite mob, Dread Fearbringer while waiting for the 60 seconds. At the third circle there will be two groups of mobs, you may choose to pull in both groups at the same time or one group at a time. Move on the the fourth circle and its pretty straight forward using Kil’ruk to assist.
It will take 6 minutes for the first Elite scorpion to respawn. so during this time head towards the NPC Jonathan Jacobsen near the breached wall and you will see waves of Ik’thik Warriors flying above. Kill Ik’thik for the time being till the scorpion is back. Then repeat this process till the buff is over.
See below for the map and process to farm Windwool Cloth in WoW.