I have heard to use freezer paper to line molds, but I'm having a tough time finding it. I am making a batch of 4th of July M & P soap. What i would like to do is take a shallower cooking sheet, line it to make a large, fairly thin soap. This would require lining the pan with a paper -- can i use wax paper or parchment? are these not acceptable? or would they do just fine?