If you have any leftovers, wrap them in foil or an airtight container and refrigerate. Italian sliders will keep for up to 3 days in the fridge. You can also freeze the baked sandwiches. Place them in a freezer-safe bag or container and they'll keep for up to 2 months. When you're ready to eat them, thaw them in the fridge overnight. Then, reheat them in the oven or microwave using the instructions below.