I made this Netherweave Cloth farming guide to help out players who want to farm the cloths instead of buying them from the Auction House. I decided to search for places with a high density of mobs that I can kill and drop [Netherweave Cloth]. I traveled around Outland, and after a while, I made a list of places.
There were no major changes to Netherweave Cloth drop rates at Outland, so this guide can be used for Burning Crusade Classic (TBC) and Retail WoW.
Mana-Tombs - dungeon
This farming place is for Retail WoW players only. If you play Burning Crusade Classic, scroll down a bit for the other farming places. But, for retail players, this is the best farming place. They can ignore the rest of the guide. (assuming you have a high-level character)
Mana-Tombs is currently the best place to farm Netherweave Cloth, but you need to be around level 40 to farm here efficiently. If you don't have a high level character, scroll down to the bottom of the guide to find alternative farming places.
(This is normal Mana-Tombs, not heroic)
This dungeon is a wing of Auchindoun which is located in the middle of the Bone Wastes in Outland's Terokkar Forest. You can find the entrance at the north of the Ring of Observance. (screenshot of the entrance)
Once you cleared the instance, go out then reset the instance by right clicking over your own portrait then click the "Reset all instance" button. This restarts the whole instance and all mobs will be back. You can only do 10 instance runs in an hour, this means sometimes you might have to wait a bit.
Legion Hold in Shadowmoon Valley is the best place to farm Netherweave Cloth. Shadow Council Warlocks die very quickly and there is always at least 3 Warlock alive. Just watch out for the roaming elite.
Manaforge B'naar is also a really good place. Just make circuits around the camp where there are groups of Blood Elves at various tents.