1/2 cup granulated sugar
1 1/2 cups water
Squeeze juice from limes and save in refrigerator for later use. Slice lime peels thinly. In a heavy saucepan on high heat, boil sugar and water for 3 minutes.
Add lime peels. Reduce heat to medium and simmer for 1 hour, or until skin is softened.
Cool on a wire rack set over a cookie sheet. Dry on the rack for 12 hours.
Refrigerate in a covered container.