1. Alcohol & Water
Mix 1 Part alcohol to 3 parts water in a ziplock bag. Compress the bag to remove as much air as possible before zipping.
Place inside a second ziplocked baggie (in case of leaks).
Lie flat in freezer.
1 or 2 bottles of dish soap inside of a ziplock bag. Compress it to remove as much as air as possible before zipping.
Place the bag inside of a second ziplock bag for more protection against leaks.
Put the bag flat in freezer for a few hours.
3. Frozen Food
A bag of frozen peas or corn works great!