I found a cool new way to make extracts without solvent. Instead, you use hot gas, either nitrogen or steam. This is a lot easier than CO2 extraction because no pressure involved and produces a higher potency product, almost pure THC actually, see table below. It's basically like short path distillation of THC but you can start with plant material directly instead of going to all the trouble of extracting with solvent or CO2 first. See patent for details. Only problem is heating the gas to 130-175 C to vaporize the THC, but still heating is easier than pressurizing.