This is best done with two players...pref a rogue & hunter, but can be soloed by hunters, priests & really crafty rogues.
Location: Dire Maul - West (best to use south entrance to the west side).
In every instance made in all of Dire maul there is a chest spawn & usually a Dusty Tome spawn. In west, there are four spots that the chest spawns, two of which can be gotten very quickly & with few mobs. There are also two Dusty Tome spawn locations (that I know), but only 1 location is easy to get to....just so happens it is about 3 feet from one of the chest locations.
In each chest there is a lvl50-55 green, some are pretty good, also some change & 1 in about every 25-50 chests have a blue BOE usually worth 60-100g. All the greens dc into Greater eternal essence & illusion dust, Or you can vendor most items for about 3-5g a piece or sell on the AH. The Dusty Tomes are where the real money is though....90% of the tomes will give you a junk book "nat pagles extreme fishing..." and pocket lint - the rest of the time you will get one of any of the blue class books (each sell in AH from 45g-90g) and an equal chance to get Furor's Compendium of Demonslaying (Warriors epic book) = anywhere from 1500g to 2400g. I have found several now and all sold within a few hours on AH for 2000g
Now the strat... You enter west on south side. The tome & chest spawn location is in the initial room you come into, before you get to Shen'dralar Ancient. As you are looking at the room from the portal, the chest will be across the room on left side (there is another spawn location on the right side - but after you do this a while, you will see it is more profitable to only look for the left side one).
If you use an Ornate spyglass you can position yourself on a corner right next to the instance portal (bout 15ft from it) and look down to the south west corner with the chest & tome. (for the first while you will want to run down and make sure nothing spawns till you know exactly where to look). If you dont see the chest or tome, run out the instance and reset it...round trip on an empty instance is about 30seconds or less. IF the chest spawns in that spot(bout 25% of the instances) there will be 3 to 4 tree creeps guarding it. The easiest way to get to them is to have a rogue position behind the chest ready to take it & have another class move up and agro the three trees then turn & run out the instance while the rogue loots. Once you get used to it, you can loot and be back to reset in under 2min.
Hunters can solo this by using Eyes of the beast & taking the agro to the other side of the instance, then dismiss their pet, grab the loot & move to a safe spot to feign death.
Screenies for those that have found this confusing...sorry I did not have them up before....
This is where you should stand to use spyglass...
Here is what you should see thru spyglass...approx....was in a hurry to get the screenies so I did not wait to find chest...but pasted in a spot where you will see them...
DM West is easy enough to move around once you learn your agro range and stay close to the south wall.
I will try to update this with pics, but I am not that great with photo stuff.