A bad sunburn is a terrible thing to endure, but cornstarch comes to the rescue once again! We aren't quite sure why, but cornstarch is very effective at soothing red, burned skin. You can make a simple paste of cornstarch and water, and apply it directly to the area; bathe in a cool bath with a cup or so of cornstarch mixed in; or mix it with water and spritz it on your skin for ongoing relief.