a

You should first evaporate some of the naphtha until it becomes a little cloudy. Then put it in the freezer.

Evap some Naptha so it gets more concentrated and easy for crystals to form, and, the more pulls you do, the less you're gonna get. Say theres 500mg of spice in there, and in the first pull 200 come off, the next one, since there's only 300mg left in there, maybe 130 will come off. third pull there's only 170 left....100 comes off....4th pull theres 70 left...only 50 come off....PerPLexED likes to ramble...point is..the less the concentration, the less you're going to get out of it..

a

I never evaporate before freeze precip. Light aliphatic naphta is too expensive here...

You need to have your freezer cold enough, also keep the naphta in the freezer for at least 24 hours.