So, i tried it... dissolved a small amount of hash oil, 2-3x the amount i smoke usually, into a bit of alcohol, then mixed it with glicerin.
The solution of hash oil in alcohol was dark brown, that turned into murky brown when i added glicerin.
The amount of alcohol was about twice the amount of glicerin. And the amount of hash oil was roughly 1/100 of the volume of alcohol.
Then i put the test tube with the mixture into a can with boiling water, and left there until all the alcohol evaporate. You can know that all alcohol evaporated when the volume of the solution dont goes smaller with the passing of time.
When the alcohol was completly evaporated (what took some 10-20 minutes), the glicerin was murky green, and there was a lot of small bits of a dark, almost black tar-like residue in the test tube.
I took only the glicerin, cooled it, and put under my tongue for 10 minutes.
After some 20-30 minutes, i felt slightly high... dont know if i went much higher than it... but, if i had eaten/drinked the (small) amount of hash oil i used, i would be only slightly high also... so, i think it actually works.
Im making some hash oil right now, and will test this technique with a greater dose... Later, or tomorrow, i will post my results.