Cream puff shells keep about two days in the refrigerator when stored in an airtight container lined with a paper towel. Freezer storage increases the shelf life to about one month. Even when properly stored, cream puffs lose their crisp texture and need reheated prior to serving.
Cool the cream-puff shells on a baking rack until they reach room temperature and wrap them tightly in plastic wrap. Slide the wrapped shells in a heavy-duty freezer bag and keep them in the freezer up to one month.
Heat the oven to 300 degrees Fahrenheit and take the cream puffs out of the refrigerator or freezer. Let the shells reach room temperature and heat them on a sheet pan until crispy, five to eight minutes. Let the shells cool to room temperature before you fill them.