well... your concerns about the purity of acetone are very reasonable. Of course it would be much better if you could make has oil with pure acetone. Anyway, most of the another substances added in it are another volatile organic solvents, which shall evaporate too. The not-so-volatile ones are the water-like liquid which remains in the dish, and are washed away. Even if something remain mixed with the hash oil, you must remember the amount of this substance would be very small (as the amount of hash smoked is usually very small too). And remember, too, when we smoke the weed, we inhale all the smoke of burnt weed, which contains lots of harmful chemicals, tars, etc, and in a far greater quantity than anything present in a small piece of hash oil. So, all in all, i still think smoking hash oil is healthier than smoking weed. :thumbsup: