Heya.
My first exploit to be posted, and I've tried to find if it was a repost, and got no results. Basically, it allows you gather more Justice Points than the cap intends you to. It's not going to show in your panel, as you don't exactly get "more JP". You keep assets which are worth JP when vendored, at all times.
I bet you already figured out how it works.
How it works :
1) When at 4000 Justice Points, purchase a piece of gear from the JP vendor.
The piece of gear will show a 2 hours window for you to get a JP refund.
After 2 hours, the refund possibility will expire.
2) After you buy the piece of gear, run another Heroic. It has to take less than 2 hours
Once the Heroic is done, make sure to get back to the JP Vendor before the expiration.
3) Buy another piece of Justice Points gear, identical to the first one you purchased.
Sell the first one you bought.
An example :
You have 4000 JP.
You buy a piece of gear worth 950 JP. You're at 3050 JP.
You run, say, Heroic Deadmines. With a competent group, you clear the dungeon in less than 2 hours. Six bosses, you're now at 3470JP.
You port out the dungeon. You're at the JP vendor. You buy another piece worth 950 JP. You're at 2420 JP, and now have two pieces worth 950JP each. The first one's refund timer is about the expire, and the second still has 2 hours refund timer.
You sell the first one back for 950JP. You're back up to 3470JP, and you have an item in your inventory worth 950JP. You have a total of 3470 raw points + 950 "hidden" points.
The key is to never sell an item about to expire before buying another one. Otherwise, you will cap on Justice Points and all the points the item would've provided that would've brought you beyond 4k will simply disappear.
The refund timer DOES NOT tick while logged out.
Of course, at the very moment, this exploit is pointless because there is nothing of value for you to buy with the JP. At least nothing worth wasting hours in Dungeons. However, come around a future patch, Chaos Orbs will likely be made purchasable through JP. If you accumulate, say, 1k points every day, that's 30k a month. By the time the next patch hits, you might have enough points to purchase enough Orbs to make a small fortune.
Just figured I'd share.
Also would probably work with stacking Honor points in order to buy future tiers of gear as fast as you want.