To a saucepan, add 1 quart sliced peaches, ¾ cup water, 1 cup sugar, 2 tablespoons melted margarine, and 1½ teaspoons lemon juice. Cook over medium heat stirring frequently until mixture comes to a boil. Optional: To thicken, dissolve 1 teaspoon of cornstarch in ½ cup water and stir into mixture.