So I noticed a lot of people on my server have been wanting to buy Blood of the Mountain in the AH i've seen the price as high as 700g, 500 the lowest. This could vary from server to server of course, Ive heard of them going for 1k each on some servers and 200 on others. Anyways the best way to farm this is have a character logged out at the attunement guy for MC (assuming you're attuned) (preferably something that can solo stuff easily). Now once you enter, follow the white line on this map:
Right when you go in and you see the Molten Giants do not aggro them you can run to the right and jump right next to the lava on that ledge, if you fail to do this it's fine you wont die from lava, just make sure you're at full hp when you pull the Molten destroyers. The molten Destroyers are located anywhere from Gehannas to Garr. Do not leave this area or you will just be wasting your time. Avoid all mobs that you can, the Core Hounds have large aggro ranges so do not get too close to them. After you kill all of the Destroyers you can go outside and go AFK for the next 30 mins, go on a different toon, or make this guide like I did haha. Now of course this isn't consistent gold because of the drop chance being ~8% but it's definitely worth it for the little amount of work that you have to do, Also if BoE epics drop (Tier gear) make sure to put them up in the AH, they sell for 100g+ depending on server.