Wash and peel peaches. Leave peaches whole. Treat to prevent darkening. Combine 3 cups sugar, salt and water in a large saucepot; bring to a boil. Drain peaches. Gently boil peaches in syrup one layer at a time 5 minutes or until hot throughout. Peaches will darken if undercooked, but do not cook until soft. Place peaches in a deep bowl. Boil syrup 5 minutes; pour over peaches. Cover and let stand 12 to 18 hours in a cool place. Remove peaches from syrup. Add remaining 3 cups sugar to syrup. Boil syrup 5 minutes; pour over peaches. Cover and let stand 12 to 18 hours in a cool place. Remove peaches from syrup. Boil syrup. Pack peaches in hot jars, leaving 1/2-inch headspace. Add 3 to 4 tablespoons of peach brandy to each jar. Ladle hot syrup over peaches, leaving 1/4-inch headspace. Remove air bubbles. Adjust two-piece caps. Process 10 minutes in a boiling-water canner. Peaches should be ready to use in approximately 4 weeks.