Frustrating when things don't go right cosmic.  Keep at it. 

Re-x procedure is basically water bath the naptha either large amount and then evap like herba luisa suggested, or else I use add in tiny increments until all my spice is dissolved assuring super saturation.

Tilt your small spice and solvent containing container until you see the colored gunk form on the bottom in the direction your tilting.

Then siphon off the solvent on top of this without getting any of the gunk, than freeze precip the new clean crystals.

Recently there was a long thread about a STB extraction done by data, here where similar results occurred that re-x couldn't seem to fix.  You may be left with a smokable jungle spice, or something that has plant fats left in it. 

Technically speaking, I have no logical or scientific explanation as to why a re-x wouldn't work on any impurities found in spice, make sure your not getting ANY gunk into your new solvent before freeze precip, and let everyone know what you come up with.

P.S. Almost forgot, welcome to the Nexus!  I'm sure you'll find the community here more than willing to help in anyway possible.  I look forward to learning with you in the future.