I used to sell weed in high school in the 90’s, buying by the pound. I’d save the stems and sticks then use wood distillation to harvest the resin. Note that this was just from the bigger stems than no one would want in their bag. Add to that the smaller stems left behind from people smoking me out and my own personal stems. Keep in mind this weed was Mexican schwag weed. The stuff people are now used to would have knocked my head off.
So, that’s not a lot, but taking about an ounce of that and putting it in a beaker under a bunson burner with a tube connected to a test tube in ice water, we’d get a few grams of what we called “hash”, but it was just concentrated resin.
Drizzle some of that on a joint before it’s rolled or a bowl before it’s lit, and we’d get lit for real.
And the stuff nowadays is probably 5-10x stronger. I don’t even smoke cannabis anymore, but I tried 2-3 hits last year was almost too high. No tolerance + the strength of today’s product would have knocked me on my ass if I had taken 1-2 more hits.