Once the naptha is seperated from the alkali DMT solution, before it is put into the freezer, it can help to evaporate the Naptha down to about 1/2 or 1/3 the quantity that was started with. This will help ensure the solution is supersaturated when it goes into the freezer.     The Naptha should look perfectly clear until evaporated down. Once it gets to about 1/3 what it was it may just start going a little cloudy. This is the point where cooling it in the freezer (or perhaps the fridge first then the freezer if you want bigger crystals) will make most of the DMT fall out of solution.    If there are really nice looking crystals that dissapear completely as soon as they are seperated from the naptha then these may be ice crystals that melt when warmed up. This can be frustrating. To avoid this the naptha must be sealed at the top with cling film or something to stop bits of ice falling in from the freezer and to stop condensation forming in the container when the naptha is removed from the freezer.      I know one guy who did the evaporation down to 1/3 with the naptha until it went cloudy and then stuck the stuff straight in the freezer. The DMT crystals formed so quickly that they were tiny and stayed in suspension rather than crystalising out on the bottom of the container. If cooled more slowly (fridge then freezer) larger crystals will form which stick to the inside of the container and can then be scrapped off the bottom more easily than having to mess with coffee filters.    If done this way a flat bottomed glass baking tray can be better than a jar because it has more surface area for quick evaporation down to a 3rd, and if the crystals stick to the bottom it is easier to use a tool to scrape them off.