1. Spit on it ....... the inside of the visor, I mean. And not a big green slimy poc - just normal spit, then wipe it over the surface till its dry.
It's what scuba divers do on their face masks.
2. Dish washing liquid ..... found this totally by accident on a tour of Tassie many years ago. While using it to clean the bugs off the outside
of the visor, I used a clean tissue and the dwl on the inside, and next morning NO FOG !
HTH ..