Doing STB, with MHRB using VM&P and sometimes Zippo fluid as a solvent, the pipetted spice filled solvent goes into small mason jars then straight to a cold freezer. Usually but not every time, there is a small canary-yellow droplet about in the center of the jar amongst all the white xtals. What is this?

Seperate ?
Doing the same method, a few jars were left to sit for about two weeks undisturbed (no turning over of jars) with the solvent. The yeild seemed considerably less... at least the first pull should be better right? Any thoughts?

Probably water. Not a problem if just a droplet or two. Make sure collection jars are dry. If you did a carbonate wash, swirl a bit of anhydrous (microwaved) epsom salt in the solvent, filter it and discard, then freeze.
L

L,
Much thanks for that reply. That would explain some things since sometimes the jars are quickly cleaned but also as quickly (or not thoroughly) dried.