One of these days I may have to try to do this just to see if I can prove you guys wrong. I have a shit ton, probably approaching 70 roaches, that I am going to try to refine into BHO but I think that is going to be much easier then refining resin. The problem with destructive distillation (the process of burning and condensing the burnt vapors) is it creates a lot of tars by breaking things down into alkanes. Selectively removing the alkanes and who knows how any other products of combustion will probably take a fair amount of doing, i dont see why it should be labeled impossible. It would be a lot easier if THC would form water soluble salts
I am almost sure i can do it with roaches because i can remove a lot of the resins and impurities by removing the burnt and blunt bits, from there i think its a matter of making a crude BHO through a standard method. This will most likely yield some kind of black nasty goo and from there its a matter of dissolving said nasty goo in a solvent and hopefully either systematically removing its components or just spinning it fast and making it separate... I have a lot more time, energy, and equipment after quitting dope. But it probably wont be for a while because it may need a centrifuge, which is cheaper then you may think