SWIM can report that recrystallising in naptha does indeed work, it can yield nice little table salt sized pure translucent crystals of dmt in about an hour after dissolving just barely in hot naptha in a closable container and then putting straight in the freezer. There seems to be a thin layer of a yellow contaminant that warm/cool cycling seems to isolate from the dmt, and further that the yellow stuff doesn't actually crystallise, it forms a resin. This, mind you, was with acacia obtusifolia, so mhrb might be a little different.
SWIM hasn't fully experimented yet, but intends to find out whether alternating the recrystallisation solution between warmer and cooler environments (room temp, fridge, freezer) progressively towards the freezer temp will eventually result in larger crystals.
The contaminants causing the extract to oil out are probably high boiling elements from the naptha, so long as the naptha isn't allowed to lose too much of the low boiling element when heating it (ie if done quickly) the much more naptha soluble crap will definitely wash off when the solvent is removed from the crystals.