Keep leftovers in an airtight container in the refrigerator up to 3 days. If you are planning to save part of the salad to eat at another time, do not toss it in the vinaigrette and store the dressing in a separate container from the salad. You will need to let the vinaigrette sit out at room temperature for 15 minutes before you toss it into the salad, because the oil will harden in the cold temperature of the fridge.