hmmm I get the Idea some are referring to a re-x in the manner that there just growing out the crystals and some are trying to isolate impurities by taking advantage of the different solubilities at different temps.
How does SWIM perform a slow re-xing? After melting his DMT in heptane, SWIM has let his container sit in a cold water bath for about an hour, then in the refrigerator for 12 hours then in the freezer for another 4-8 hours.
hmm yes doing it slow I find is the only way to go from yellow to clear...
first of all for this the taller-skinnier the vessel the better....
with heptane I like to use 35ml per gram of spice.
for best insulation to allow the heptane to cool the slowest you will need a mini cooler (i like the gallon sized round ones).
fill the cooler with hot water around 140F. to the level the vessel you are using stands..
place heptane and spice in your vessel and heat up using a hot water bath until all of it is dissolved.
now quickly place your vessel into the cooler so that it's submerged in the hot water and close the lid.
leave at room temp for a couple days,
leave in fridge for a couple days,
now the freezer for a couple days,
during the whole cooling process you want to have the cooler leaned at a 45 degree angle this makes the impurities bunch up better.
once you take it out of the freezer you should see a glob of nasty orange goo on the bottom and clear/white crystals that are very hard and dense on top and all around the sides, they are very easy to scrape away from the gooey mess.
anyways this method is what worked best for me to clean up goopey shit with heptane, never could I just decant at the right moment or such.
however i'm still not to fond as I feel like I always burn spice away from leaving the spice in to hot of heptane for too long. when theres lot's up impurities one MUST go over 140F. to dissolve everything.
well this is what I have found through trial and error hope it helps.