Common sense should tell us when it's bitter cold don't leave vulnerable possessions in the car. Some of the items you should bring in might surprise you. It's better to know than not know so here goes:
1. Cell phones. Mostly because the batteries are vulnerable to cold temperatures.
2. Musical Instruments-which could crack or get out of tune.
3. Medications-Some loose effectiveness when they freeze.
4. Eggs- The liquid expands and they crack. If this happens they are garbage. Frozen eggs that don't crack can only be hard boiled.
5. Beer and Soda-These liquids also expand and break their containers. Same for canned goods.
One more thing. Make sure your gas tank is at least half full at all times. If not, your fuel lines could freeze.
Source: USA Today