This one comes from my grandmother:  Fill old milk jugs up with water (leave a little air in the bottle for expanding ice) and put them in your freezer.

 How does this save money?

  1. Water holds it’s temperature better than air, so once the water is initially frozen, the freezer doesn’t have to work as hard to keep things frozen (think oldschool ice boxes).
  2. When traveling, you don’t have to buy special icepacks since you have them in jug form. (you can also use old soda bottles or anything else that’s watertight)
  3. If your home is ever invaded, you can lob them at your enemies.

Has anyone tried this before?