Fog-be-gone spray or other brands , can be found at snowmobile shops or online (i wear glasses and use it during winter hunts on glasses, binos, scope.
Couple of these "fogging" threads floating around right now. Same response I posted in the other thread...
I picked up some dealer samples of Op Drops from McNett at SHOT a year or two back and I am sold on their products and highly recommend them. I run the Op Drops on my glasses, scopes, Binos, LRF and spotter. It is great stuff!!