Which answer would you prefer, the 'high tech' version, or the
'bargain basement' one? FOr the former, there's this stuff you can
buy from REI (the outdoor goods place) for about $4.00, called "Cat
Crap" (honestly - I'm not making this up!), which you can smear on
the lenses, wipe off with a soft cloth, and go for about 6-8 hours
with nary a glimmer of fog. Then on the other hand, there's a product
that's most likely in your bathroom, as we speak, and will do the
exact same thing, at no additional charge! It's called shaving cream.
You don't need a lot - just a tiny dab on a fingertip, smeared around
in concentric circles on the back of the lens, then polished off with
a piece of microfiber or other such fabric. All any of these realy
needs to do is provide a barrier between the moisture and the lens.
In a pinch, a judicious application of your tongue will even do the
trick, but I sure hope no one else has to use those lenses, if you
Glad to help out!