I dont know if anybody tried, but if you are willing to, try it out and let us know.. The thing with freeze precipitating DMT out of naphtha is that luckily enough, at freezer temperatures spice precipitates but most impurities dont. With dry ice and xylene, it might be that you dont get any precipitation, or that you precipitate only part of your dmt, or that you precipitate all of your dmt and no/very little impurities, or it might be that you precipitate both your dmt and impurities... Only one way to find out

By the way, the best way IMO to get spice out of a xylene solution is to salt it out, most notably with FASA to get fumarates (but other acqueous acidic solutions would work as well)