As you can probably tell by the title, this requires a Death Knight, not entirely, but it makes your life a lot easier. Let me explain. This requires a bit of leveling:
In Dire Maul arena, 2 mobs spawn, Skarr the Unbreakable (Skarr the Unbreakable - NPC - World of Warcraft) and The Razza (The Razza - NPC - World of Warcraft).
Now, both of these mobs drop multiple BoE blues, and are easily solo able by a DK of level 65 or higher. The best part is, you can camp a DK alt there, play on your main, and check frequently to spawn.
From the BoE blues, most won't sell for much due to the ~58 greens from Outlands, but, both of these rare spawns drop Orb of Deception (Orb of Deception - Item - World of Warcraft) which, depending on your server can sell for upwards of 500g!
This is an easy way to make gold by just checking an alt every now and again. Enjoy. :wave: