Non-Alcoholic Margarita Punch
["1 (12 oz) can frozen lemonade concentrate", "1 (12 oz) can frozen limeade concentrate", "1 c powdered sugar", "4 egg whites", "6 c ice, crushed", "1 liter carbonated water", "1 lime, sliced", "coarse salt"]
["In a 4 qt container combine lemonade concentrate, limeade concentrate, powder sugar, egg whites and crushed ice. Mix well. Cover and freeze at least 30 minutes before serving. Spoon 2 cups slush mixture into blender. Add 1 cup of carbonated water. Blend until frothy. To serve, rub rim of glass with lime slice, dip in salt and fill glass."]
["frozen lemonade concentrate", "frozen limeade", "powdered sugar", "egg whites", "water", "lime", "salt"]