I hear there's a brand PURETAIN that is 9x. Google it. Says 99.998% pure on the blue and white can. I was going to get some but I can't figure out how to evap the stuff without a nineteen hundred dollar vacuum oven. I'm not spending that much and I don't trust anything else to get the toxic residue out. Guess I'll just keep screening trim leaves for hash for now. Love to try the butane thing though, sounds like a project for the future.