Fractional distillation unfortunately. We ran a rig to help pull off THC from any crude CBD extract that ran hot. Definitely not my preferred way to do things as you can lose a lot of terpenes as well as other cannabinoids if you overshoot your heads and tails.
And the smell, dear god the fumes were like concentrating the compounds that make you cough and aerosolizing them in a room. Definitely not something to do without a fume hood or a strong canister filter mask.