Back in the 80's, a buddy of mine had a machine called an Isomerizer.
He would grow some weed, hidden away somewhere on 20+ rural acres of his parents' property. After harvesting, and separating the buds, he would break up all the leaves, stems, etc. and store it away in a freezer for later. 'Later' was whenever the buds ran out, so when 'later' came around annually, he would pull out the Isomerizer(which he purchased via mailorder in the late 70's), and put it to work! I will try to include a picture of one that I just found on another website, if possible. This machine looks like some special effect piece you'd see in a bad, b-rate 70's sci-fi movie, but it worked, and it was AWESOME at what it did. As I remember, you'd put grain alcohol in the bottom basin, hanging above that was a basket with a screen bottom that contained the otherwise unusable leaves and stems. All that sat inside of a cylinder, covered by a tall lid that was shaped like some funky electrode, or electrical insulator with fins circling around it. There was a light bulb built inside this machine, at the very bottom which acted as a heat source to slowly evaporate the grain alcohol, which rose to the top as a vapor, then condensed onto the inside area of the funky cooling fins, then the droplets would drop down through the basket containing the weed material, somehow extracting the thc from the weed, which then collected in a little pan. This took like 2 or 3 days of running the machine constantly. After it was finished, you had a pan filled with black, sticky, extremely potent hash oil that was retrieved from useless, throwaway debris! I was smoked by all of us through a home-made glass pipe
which was melted at the end, forming a ball with a small hole in it, where the hash oil would be added using the tip of a dart. We then slowly heated the glass pipe with a propane torch(with care), and received the smoke. This stuff would stone you up in just a few small hits, and it tasted and smelled like nothing else. I was fortunate enough to be able to partake in this every year, for about a decade, til my buddy(who was/is 10 years older than I) grew out of partying when he hit his late 30's.
I thought I'd add this in hopes of someone else remembering the wonderful, recycling qualities of the Isomerizer, a machine that seemingly hasn't been produced or sold for a long time. I occasionally see a blog(elsewhere) where someone will ask what an Isomerizer is/was, and then some know it all will claim that he had heard of one, and it didn't work, or some-such non-sense. It was based on simple solvent extraction processes that are used everyday to create your 5x, 10x, etc. extractions, so it is just common sense that it would work.
So if you are lucky enough to get hold of one of these from some old-schooler, you will soon be creating some ass-kicking home hash oil, that will
recycle your stems/leaf, and amaze your budz!