Decarb the crude fully, then dissolve in your favorite alkane solvent (pentane, Hexane, Heptane). Do several flushes with a highly caustic brine (spike your salt water with sodium hydroxide to acheive a pH of 12+). Bring the solution back to neutral by flushing with distilled water and verify that neutralization has taken place or you will have isomerization issues later. Also make sure you dry out your suspension with a dessicant (mol sieve like Cbeads) prior to recovering your solvent.
The reason this works is the kpa of THC is 10.6 - we are essentially making it water soluble by exposing it to a pH of >10.6 - THC levels are very low in your Hemp-Based extract and after a few rinses we should have a remainder of mostly CBD + other minor cannabinoids.
Save all your water if you care to neutralize and extract the THC from the byproduct 
Cheers.