Wondering if anyone has ever tried this (http://I.imgur.com/7E2bXt0.jpg) for there warm up? It is filled with corn and can be frozen or heated for headaches, muscle aches, etc. I read on the beginner basics that a sock with rice is a good alternative. I’m assuming this would be equivalent to that? Had this thing for years in my freezer and never once considered using for my warm ups.