Washed healthy and mature prunes are divided in half and remove pits. Arrange in pan and sprinkle with sugar. Stay cool for several hours, preferably overnight. Mix, then add vinegar, water and cloves, and all ingredients are mixed well. jam bake in a moderate oven until thickened, as occasionally stir. It is ready when a drop of syrup dropped onto a porcelain dish, do not spill. A few minutes before the jam is removed from the oven, sprinkle with cinnamon and stir. hot jam is packed in dry, warm jars. Close airtight lids. Jars turn down the caps to their full cooling. are stored in a cool dark place.