This post is for demonstration purposes and likely would never be incorporated into any sort of commercial process but my intent is to document what I do to purify and never to document how I believe others should.
The ceramic bowls used have a thick base and generally wick the heat away from the rubbing alcohol. The water in the rubbing alcohol wicks heat away by evaporating. So all in all the extract itself is generally not all that hot. Heavy ceramic so far is the only thing that allows me to do this without serious flare ups. The vessel and surface it rests on must be able to sink the heat of combustion.
This method targets the cracklies and poppers for removal that seem so bloody hard to get out with molecular distillation alone. As a singular process I found doing this all by itself mellowed my extract out considerably and it is basically how I started down the path with refinement I am on today.
Before you try this I will also tell you I damaged a BUNCH of extract trying to do this with fresh crude. Expect to douse wth a lid often and ALWAYS allow everything in sight to cool down to room temp before relighting.
Final warning: if you attempt this procedure in any other way than demonstrated then you are in uncharted territory. I cannot imagine any deviation from what is presented to be a net positive because I have developed this from scratch and burned up a lot of concentrate doing it.
Do not attempt a different solvent system as this particular one is the only possible one I can envision that will work. Others would not work AND would be extremely dangerous to try.