Your next faceshield? There's gold in them there shields!
The tech news site I read had a link to this article. Seems a nano-particle coating of gold will prevent fogging. Keep in mind that gold can be rolled out to only one atom thick, as is often the case with gold leaf (though I suspect most gold leaf is a few atoms thick to make it easier to handle). In other words, maybe a dollar's worth of gold to anti-fog your faceshield?
I suspect our faceshieds won't be first on the list of products to use this tech, but it may be something coming. (I have a Uvex shield with an anti-fog face plate and it still fogs up, so if this works I would be interested.)