In a small saucepan, combine ketchup, pineapple juice, sugar, and vinegar.
Heat over medium heat until mixture comes to a boil. Boil, while stirring, for 2 minutes, remove from heat, and cool.
Notes
Recipe makes about ¾ cup sauce.
Refrigerate sweet and sour sauce in a cruet or jar with a tight-fitting lid for up to 2 weeks
Freeze sauce in ice cube trays and add to favorite recipes. Once cubes are frozen, pop them out and place in a zippered freezer bag. Store in freezer for up to 3 months.