Defrosting a Gas Cap 

Holding a small plastic bag with warm water against the fuel door is very effective. It will perfectly adapt to the shape of the fuel door and have the ice melted in seconds. You can fill the plastic bag at your gas stations toilet/restroom. The plastic bags have several practical uses in a car. Like collecting garbage from snacks, emergency rubber glove alternative, water dispenser if your coolant is low.

Thanks alot!