I ran into this problem several times during my most recent extraction. It was an A/B from Chaliponga leaves (about 100 grams). I did 3 acetic acid soaks at pH 4, defatted a bajillion times with naphtha, then basified with NaOH to pH 13 or so, and then proceeded to do my naphtha pulls, while the solution was still warm. But the problem is: The dark NaOH solution sticks to the side of the glass bottle that I'm using. Not a lot, but the whole wall of the bottle surrounding my top layer of solvent is covered in little specks of black. Even after waiting several hours for separation. I've tried everything, heat bath, warm naphtha, cold naphtha more gentle agitation.... I resorted to using my pipette as a sort of jet, squirting naphtha to dislodge the residue off of the side of the bottle, after which it would fall back down where it belongs.

I'm guessing that it's just friction with the glass that's making the aqueous layer stick to it, but I was wondering if anyone else has run into this and if anyone knows any tricks

of course it does.
the surface of glass (silica) has silanol groups. what you're witnessing is hydrogen-bonding between the aqueous phase, and the silanol groups in glass. this is normal.

So should I just do what I did and try to physically dislodge it or is there a way to prevent it from happening? I suppose a different type of container would be good. What kind of material would not cause this effect?

Or should I just not worry too much about it and make sure I do the sodium carbonate wash thoroughly?

Have a look at the pics in the pdf to download here.
Perfectly normal...don't worry about it.

Oh great, that looks like exactly what I had, good to know. Though my naphtha was very yellow.... Do you think that's maybe an inevitable result of using leaves because of the lipid content? Or maybe I let it get too hot during the acid soak, or maybe the naphtha was too hot....

so many factors...

Regardless, if I can get a product out of a Chali extract that isn't a goo, I'll be pleased

goo isn't pleasing?!?

It seems there are lot of you goophiliacs out there, and I must say I've never tried it, so maybe I don't know what I'm missing yet. If goo's all I can get, I guess I'll find out, but it would be much nicer to have something resembling crystals, even just for the stake of storage and hassle. Maybe my mind will be changed in the near future and I'll convert to the religion of gooism