1- Boil some water. Turn off the fire.
2- Add your impure spice to a shotglass (weigh it before to know the amount).
3- Add around 20-30ml of naphtha/heptane/hexane per gram of impure spice to the shotglass.
4- submerge the bottom of the glass in the water. Leave it standing and/or stir it around a little bit. Most of the spice should redissolve in a few minutes, but probably a layer of goo will stay on the bottom.
5-Decant or pippette your naphtha away from the goo, put this naphtha in a clean container, close it, and into the freezer overnight for freeze precipitation. Alternatively, instead of freezing, if one wants to grow large crystals, put in a container with the lid semi-closed and/or in a place with very little air circulation, so that the naphtha evaporates very slowly. The slower the evap, the larger the crystal growth.
Its possible small amount of spice is still in the goo, so you can add another 5 or 10ml to the shotglass with the goo to pick up the last bits of dmt. This second pull will be more impure as it will pick some oils up, so freeze precipitate it separately. The goo can then be discarded