I have seen toothpaste being recommended as a way to make your goggles fog resistant. I would like to know 1). How well does it work? 2). How much should I put on for best results? 3). How will I know when it is rubbed in all the way? 4). Is there a certain kind if toothpaste I should use? 5). Do I wash it off the goggles or let it sit?