Silicon and other minerals in oats help relieve the itching and inflammation of sunburn, says Cox. Grind 2 tablespoons rolled oats (not instant) in a clean coffee grinder or blender until they become a fine powder. Pour the oat powder into a small bowl and mix with enough cool water to form a paste. Gently apply to your face and neck and leave on for 5 to 10 minutes. Rinse with cool water and pat dry. To treat your entire body, grind 1/2 cup oats to a fine powder and pouring them into cool running bath water. Soak for 15 minutes and rinse with cool water.