Need ice for summer events? Turn to the humble milk carton! As you empty them, drain, rinse and refill square milk cartons with clean water. Leave an inch in the top for expansion, then tuck into the freezer. Use frozen cartons whole to cool ice chests. For crushed ice, turn the cartons sideways and smack smartly against a concrete floor on all sides, then tear open the top and pour. Energy saving bonus: keeping freezers full cuts energy use.