petroleum ether is the best thing to use. Understand though that it isn't just a specific substance. It is a general classification of hydrocarbons, and will usually be classified by its boiling point. It is very flammable, and you have to be much more careful with it than most other substances you can use (except chloroform). You don't reflux the pet ether though, usually you would use something like pure isopropyl or ethyl to reflux, then you would do an extraction using the pet ether. Anyway, acetone works too, and is much easier to get.
View attachment 1163908 Making hash is concentrating weed, not purifying it.
And acetone is the better solvent. It evaporates cleaner, and leaves less residue.
pet ether is typically a better solvent for extracting cannabinoids (non-polar) than acetone, though they are close. It's hard to get though, slightly more dangerous than acetone, and I think it might be used for making meth or something.
Hash oil is actually what you would call an extraction
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Hash is more general, and can be oil mixed with carbon, or a mechanical extraction of oils and smaller amounts of carbon.