If you do have any leftovers, then let them cool completely and then add them to an airtight container and store them in the refrigerator for up to three days. This is the perfect meal to batch cook or make ahead for lunches. You can also freeze these meatballs. You could freeze them raw or cooked. Add them individually to a baking sheet, and then once frozen, you can store them in a freezer bag. Make sure they are defrosted before you cook or reheat.