Well, if you get the amount of lime just right, de-tanninised vodka extract seems useable as-is for putting into a brew, so it would also appear reasonable to suggest that evaporating it down - maybe after adding a little acid - would be good enough for capsules. Maybe even, without adding acid, it could be evaporated down for vaporisation. I also wonder if a citrate goo from this vodka/lime method would work in e-juice.

That doesn't really answer the question about naphtha, except to say now, that if you have freebase DMT in crude form there's every reason to suspect it can be cleaned up by dissolving in naphtha and freeze precipitating it. I just wonder how well the DMT would partition into the naphtha from vodka, since ethanol is clearly the far 'better' solvent in this case, in terms of sheer dissolving power at least. Naphtha is useful to us precisely because it doesn't dissolve the DMT so well - a nice illustration of how "better" works subjectively in this context.