Sweet and Sour Sauce

3/4 unsweetened pineapple juice (one 6 oz can)
3/4 cup cider vinegar
3/4 cup sugar
6 tblsp ketsup
3 tsp cornstarch
1/4 cup soy sauce

Mix all of the ingredients together in a medium saucepan. Cook over medium heat, stirring grequently, until the mixture comes to a boil and the sauce is clear.