1. To protect cookies from air and humidity that can make them stale, keep them in tightly-covered containers. Store bar cookies this way or in the baking pan, tightly covered with plastic wrap or foil. Store moist and crisp cookies separately to avoid softening the crisp ones.
2. To restore moisture to soft cookies that have begun to dry out, place a wedge of raw apple or a slice of bread underlined with waxed paper into the container with the cookies and seal tightly. Remove the apple or bread after 24 hours.
3. For long-term storage, freeze baked cookies in freezer containers or plastic bags for up to 12 months. Before serving, thaw them in the container or plastic.