Just so you know I have used the frozen method several times with NO...repeat...NO problems with passing AS LONG as temp is right (which is easy for me due to practicing with water). The way I thaw it out is just remove from freezer a day before you need it and place into fridge. I allow a slow thaw. Then I pull sample out of fridge an hour before I need to go for test and allow to get to room temp. Nuke for 10 secs like QF and secure in place. Hope this helps.