Sooooo Butane is hella expensive locally. $9.00 for the big 320ml can. I can get heptane a lot cheaper $14 for a quart. It's available at Michaels Arts and Crafts stores all throughout the country. It's sold under the name Bestine Rubber Cement Solvent. Problem is it's no pressurized. So I put the heptane in a glass bowl with some bud/trim stirred it for about 30 seconds and poured through a coffee filter into a pyrex dish. It evaporated nearly as quickly as Butane but didn't bubble or boil off as fast. This is the part that concerns me. The oil looks the best I've ever made but I think the Heptane may be harder to remove from the final product. Any chemists here?