Just a quick question.
When recrystallizing and the dark gunk has precipitated and fallen to the bottom of the glass, what is required next?
Some have said to decant (pour off) and evaporate and others have said to use a dropper to remove the gunk from the bottom of the glass then leave the clear naphtha to evaporate. Which is the better option? Also, is it better to freeze precip the contaminant free naphtha or just evap open at room temperature?

You should just be able to remove the gunk by letting it sit, then careful pouring imo, don't let it sit too long though, or else it`ll cool and crystalise in whatever you are using.
After that, cover ensure it`s sealed, then sit in the freezer.
Once that is done (up to 24hrs in freezer, 4 hours I believe is sufficient to get most out), the DMT will crystalise on the sides and bottom.
Take the container out the freezer, pour off the Naptha, and then keep the crystals.
Note: This Naptha can be reused, and saves on resources of you do, so it is encourage (plus cheaper for you too).
Let this dry over a fan to ensure it`s dry before knocking the crystals out.
Best of luck.