I made this Fel Scales farming guide to help out players who want to farm the leathers instead of buying them from the Auction House. I decided to search for places with a high density of mobs that drop Fel Scales. I traveled around Outland, and after a while, I made a list of the best places where you can farm Fel Scales.
There were no major changes to Fel Scale drop rates, so this guide can be used for Burning Crusade Classic (TBC) and Retail WoW. But, Retail WoW players should learn Outland Skinning from Seymour in Shattrath City before they start farming, or you will get a lot fewer leathers.
Killing Ravagers in Hellfire Peninsula is one of the best ways to farm Fel Scales. All three marked places have quick respawning mobs, and you can farm at any of them. There is not much difference between the three. Higher-level mobs don't seem to drop Fel Scales more often, so it's best to stick to farming lower-level mobs because you can kill them faster.
Another good place to farm is at the Dead Mire in Zangarmarsh. You will find a lot of Marshrock Stompers and Marshrock Threshalisks in the marked area.
Kill and skin Ironspine Chompers, Dampscale Devourer, or Dampscale Basilisks around the marked areas.