I just heard about this at physical therapy! Homemade Ice packs: 1 part rubbing alcohol to 3 parts water, gets really cold, but never hardens so you can manipulate it. every athlete (or mom) should pin this!
Also on these boards
ice pack , seal one end of whatever size you want to make. Mix 1 part rubbing alcohol with 2 parts water. Seal. I go an extra step and place that in another bag and seal that. You now have ice packs in sizes you need, and with the rubbing alcohol it never gets frozen hard, at most just a pliable slushie consistency. Freeze over and over for ice packs whenever needed.