At first I had some problems with my freeze precip crystals sticking to the sides of the jar and being very difficult to get out, but after changing the following Ive had no such problems..
First I began slowing down the cooling process, started with heated naphtha and letting it cool slowly to room temp, then slowly to fridge temp (in and out of fridge a few times over half a day) and then into the freezer for another day or two. This helps the crystals grow a little larger and chip off the sides cleanly.
Second I made a special top for the jar to pour the naphtha out. The top just has two small holes punched in it, this allows me to pour out the naphtha with the minimum amount of needed air (which has water which condenses on the sides) getting into the jar. I then put the airtight top back on, put it upside down and let it slowly warm to room temp before opening. I let the few drops remaining in the jar into a dish to evap and catch any spice left in it.
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