I've been using a product called Z-Wax, and anti-fog wax made specifically for lenses. It's made by a company called Zooke. I use this on the inside of my helmet lens and on my glasses. This is the first anti-fog product I've tried that really works as advertised. I purchased mine through J&P Cycles but it can also be purchased from their site at Zooke Anti-fog | Sunglasses, Goggles, Windshields, Camera Lens