I left bagged cookies (tied tightly with ribbon) in a hot car for a day. They had a lot of condensation on the inside of the bag and the frosting had what looked like what people think of as butter-bleed. I thought they were ruined but I took them out of the bags and dried them in front of a fan and they were as good as new. I rebagged them and they looked and felt perfect...for what it's worth!