Sorry I was under the impression this happened on a cold day, I have fogging happen on cold days with lots of face area bundling up and have to pay attention myself. And you said it happened alot, seems like something you could correct by changing some habits or something. Millions of people run around with gogs that work
Pretty sure I've fucked off most of my anti-fog, didn't really know that until a couple months ago (not new gogs)...next time...hehe .. the new Smith IOX has an antifog that is actually structured into the glass instead of being a topical addition, but its $$ and as I said I'm an Electric guy.
Honestly if you really get your goggles all fuxxored from a wipeout, your best bet is to go inside, have a beer and get everything dry properly for a few minutes. If it's cold and snowing its gonna be like trying to get rid of sand at the beach.