Actual research on the matter is super illegal, but observations suggest that there is a finite amount of energy contained within it but it has a strong tendency against burning clean, so use of it results in fragments, particulate, or other waste that will still do bad things to wherever it ends up but doesn't have enough power left in it to be worth trying to extract.
What the Jades do with it is something they're pretty quiet about. On the surface level because it's Jade Order business and secretiveness is the default, but possibly also because it's Druidic in nature, or because it involves something that could be considered touching the bad magic to an unfriendly eye, or because it might involve physically collecting up all the leftover warpstone and hiding it away somewhere.