Soak sliced apples before storing them. Use 1/2 teaspoon salt mixed with 1 cup of water, soak for 10 minutes, then rinse with water. Alternatively, use 1 tablespoon of honey and 1 cup cold water, soak for 5 minutes, then rinse. Portion the slices, and place them in an airtight container or resealable bag, pressing out as much air as possible for 3 to 5 days.