Wow that is a new one completely. I would recommend buying hash from the new dispensary, I think they are opening soon within the next 4 months. and herb that is grown correctly even when improperly flushed the hash yielded from the plant still has less of the chemicals. Chlorophyll is the chemical I am concerned about. and it is in all bud when smoked. Possibly try water curring your buds. This type of curring gets rid of allot of chemicals even chlorophyll. not completely but I think up wards of 90% more chemical free than other methods.

Search for water cure, their are methods here on the site. It is basically soaking your bud in cold water for a week while periodically renewing the water. then quickly drying for smoking or eating or vaping.