So I was having trouble with the inside of my helmet visor fogging up when I would be stopped at stop lights. When I'm actually going, I have not problem at all, the wind flow keeps the visor as clear as can be. I know all I have to do is lift the visor up a tad to provide ventilation, but I like to ride with mine completely shut.
So I did a little research with our helpful friend google and discovered Cat Crap. It's an anti-fog lens cleaner for ski goggles and what not, but I heard it also worked great for motorcycle visors. So I picked up a small container for about $5.50 and took ~5 min to apply it and it works great! I sat with my helmet on breathing heavily for about 5 min. (if you didn't know what I was doing, you probably could have swore I was having an asthma attack! haha!
) and it didn't fog up even once. So, I just thought I'd pass this info along. I'm sure many of you know about this product, but maybe some of you don't. Very worth it IMO.
