There's 3 basic hash methods, bubble bags can produce easy tasty hash, not all that efficient though its hard to remove all the trichs without getting plant matter, it also won't be quite as pure.. bho is made with butane, its dense and collects so you need to do it outside, being aware that your working around explosive fumes. The butane used needs to be clean, spray on a mirror then evap look for residue and icky mercaptans ect. Its a lot more work I guess. You can look up thermos methods or whatever but but basically butane runs through or soaks in the weed then you evaporate away the butane, to remove it all you should use a vacuum or etoh wash. If you really want heating it using a double boiler or similar can be used to "purge" trace amounts won't do a bit to you, your inhaling butane all the time from your lighter anyway. So the bho has generally highest potency and is selective to the thc and nit picking up any plant matter or chlorophyll...iso is my preferred method, in contrast to bho it is not selective and will result in a more amber or red oil higher in cbds ect. Iso however is not as dangerous as butane and can be done indoors, well ventilated obviously. You also don't have to take the same steps purging it as it evaporates completely clean. 99% iso is what you want, it is very aggressive, you will want to freeze it and the bud to slow chlorophyll pick up. Simply pour over ground bud through filters then wait. It can be made poorly very easily if you let it sit in iso too long. Bho is pretty much fool proof. I recommend iso or bubble bags to beginners. If you want actual detail or explanation of each or even chemistry I can go more into it. But there are a lot of good threads on here and knowledgeable people...also look into winterizing if you want a better product. Peace
Guess I could a put some spaces in there or somethin.lol that's what happens when i get high while typing and start rambling