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.

Garnish with lime slice.