If you're not in a huge hurry, just put the part in the sun. I found this to work even in the wintertime (sorry for those of you in the so-called Midwest, in Arizona we have sun in the winter, except on the days it snows). Using a pipe or paper tube to roll up the plastic on larger parts is a nice idea. If you dimple before peeling (in order to avoid the dies scratching the alclad), be sure to check all the dimples for leftover plastic. The dimpling process can cut the plastic at the edge of the dimple, leaving you with little 'O's of plastic.