Campfire Popcorn Satchels

Has anyone tried this? I would think the string would catch fire. I am trying popcorn over an open fire soon but thinking to get one of those disposable aluminum pie dishes you find in the baking section of every grocery store, putting the popcorn/oil in that then a tent of foil on top. Poke a stick through the pie dish and then that allows me to shake the pie dish over the fire with no risk of a string catching fire, or the stick.