Is it true that putting vinegar on your glasses, stops it from fogging up in the winter?

I never tried that. What worked for me was using rain-x formula on the lenses. No more fog!! You have to keep wiping the haze off after putting it on, after that you will not get fogged up glasses anymore.

I never heard of that either, but I bet it would leave an unpleasant smell on your glasses.

There are lots of anti fog cleaners/solutions available at any optical store...that don't smell.