Leftover pie should be stored covered and can stay in the refrigerator for five days. Unbaked lemon icebox pie without the meringue can be frozen. I recommend storing the entire pie uncovered or loosely covered in the freezer. Once the pie is frozen solid, you can wrap it a little more securely. It will keep in the freezer for up to three months. Allow the pie to thaw overnight in the refrigerator before proceeding with the meringue and bake as usual.