A friend's husband asked my help preparing "microwave-ready" sweet potatoes. Never having seen these before, I peeled off the wrapping, pierced the spuds, and nuked conventionally. Today he called from the market, telling me they should have been left wrapped, and not pierced. Seems 1. unsafe to leave food tightly wrapped in whatever the clear wrap is and 2. not to pierce to allow steam to escape. What is the story with this product?