winterizing is when you take your bho and dissolve it in ever clear 95% alcohol or better, and put in the freezer for 24 to 48 hours. then filter it on to a pyrex dish and place on a griddle at low heat 110 degrees with a light fan blowing over it. after a few hours all the alcohol will evaporate off you might have to leave it over night. i will place mine into my vac chamber and purge it some more. but you can effectively remove all of the solvents this way, it might take some time but it can be done. it is alot cleaner because it actually will pull out the fats waxes and lipids that the butane grabs.