[Spirit]

If you are level 5X. The best way to decomp is go to Vine Tomb. In the back of Vt, there is bunches and bunches of Sap T2 (reg. quality) and sometimes you even get Sap T3 (high quailty). What I normally do is start on the path going to the gate in Goblin camp, circle around to the left before going out the gate and continue to make circles. By the time you farm one section, they are respawning in the other.
If you also comp mats, you can go farm for an hour or so ( you will be amazed at how much you can get), then decomp all the sap down to T1, then comp it back up, then rinse and repeat. If you do not comp mats. Just decomp all the sap, sell it to an NPC and go farming again. The sap is the easiest thing to farm, since there is tons of it and at 5X, you shouldn't pull agro on anything except maybe the procks (depending on how low in your 50s you are) and even if you do pull agro, they are easy to take down.