Some time ago I ordered a small box of FOGTECH's singles packages. They are anti-fog solution in what looks like a wet-nap. I have not tried the liquid-in-a-bottle offering, just the single-use packets.
I have used them several times now for Airsoft - both in Bolle goggles and in eye-countoured goggles - and in different weather and conditions (rainy and cold, wet and hot, dry and hot).
I tested them by treating one side of my goggles with FOGTECH, and the other side with common dish soap. I also sometimes swapped for untreated goggles.
THE SHORT STORY:
Fogtech's offering works just as well as (but not noticeably better than) a good dish soap treatment on the lenses. BUT it is orders of magnitude easier to apply and far less messy. Especially handy for goggles with rubber surrounding the lenses which otherwise makes it tough to work around with a cloth and goopy dish soap.
(For the record and comparison, dish soap is some of the most effective antifog treatments I have ever used.)
Full review (slightly longer version)
HERE
Manufacturer's site here:
http://www.fogtech.ca