Hello, I did not see a guide on this so sorry if someone has already made one.
How to find Ancient Guo-Lai Cache, How to open it & what is the point in it?
Ancient Guo-Lai Cache - Object - World of Warcraft
I will try and answer all of these questions!
First I will start of with the basic's, "Ancient Guo-Lai Cache" requires "Ancient Guo-Lai Cache Key" to open the chest.
How to find these "Ancient Guo-Lai Cache Key"?
To find these you must kill mobs, there is a list of them in the link below. So you can check that out. They don't have a great drop rate, but you do get them now and again.
Ancient Guo-Lai Cache Key - Item - World of Warcraft
How to find Ancient Guo-Lai Cache Chest?
You want to start heading to "GUO LAI DEPTHS".
You will see a cave like entrance, go down and you should see a 2 doors, 1 straight forward and 1 to the left.
I believe the chest can spawn anywhere in this place, but the thing that most people don't know if, how to get through the doors, because they are always closed.
The method I use to get through them is take off all my gear, and get a mob to kill me next to the door. Then you can simply walk through while dead and res on the other side.
Use this method and just look around for the chest.
What is the point in farming these Keys?
Well, they give valuable loot.
They usually give you Gold, Spirit of harmony, Items that give rep to Golden Lotus, Recipies.
I have heard that you can actually get Skyshard. So GOODLUCK!