always used everclear man.. never heard of qwiso, ive been out of the mainstream loop for like 14yrs man, i take it be the same as alcohol extraction, or RSO.. made RSO since the turn of the century man.. I never had any rso lab tested, so IDK if everclear is "dirtier" or what, or if ISO is.. i know the canadians use industrial solvents.. it was just always easier for me to locate and pick up a bottle of everclear, i guess is why i always used it.. I mean, as long the solvent is totally evaporated then it doesnt matter, right? It would be cool to see several kinds of RSO tested..
my method is more of a "rinse", than a "wash", in the sense that i'd pour everclear over product in a container. and like 10sec later, strian it in cheesecloth. then id use the same strained liquid and pour it over the product a 2nd time. strian like immedialty.. or even have your product in a kitchen strainer lined with layered cheese cloth and whilst holding the strianer over a container, pour the evercelar,. so that immediatly runs out.. In modern terms, think like BHO.. that shits runs right through immedialty, it never sets for an extended period of time. the longer your product sits in solvent, the more chorophyll is picked up. solvents are strong man, it only takes a split second for them to dissolve resin glands.
and final step is obviously, to evap the alchohal.. passively with fans or with low heat and fans..