I'd go for ethanol caus it's food safe. Maybe you could even purify it further. You could dissolve the BHO in ethanol and put it in the freezer for a day. Waxes and fats will clump togehter and can then be filtered with a coffee filter. Then the result could be evaped. This might result in crystal clear, rock hard shatter.
Everything is always okay in the end, if it's not, then it's not the end.