Favorite window anti-fog technique?

[sciphi]

What's your favorite way to keep your windows free of fog during the winter?

Mine is keeping the inside glass clean as a whistle. The rationale is that the water vapor will stay in the air if there's nothing on the glass to nucleate a water droplet with. I may be wrong, but darned if it doesn't work a darned sight better than Rain-X Interior (anti)-Fog that I've used in years past with horrible results.

 

[JHZR2]

Keep them clean. I agree. And it isnt a case of fingerprints, snot, grease, spit, ketchup or anything like that... It's merely the offgassing of plastics and the film that comes from that...

 

[Errtt]

Years ago I remember dad used to take a bar of bath soap and rub it all over inside the windshield, then wipe it with a rag till it looked clean. Actually worked to an extent - don't recall what soap it was, just remember it was the bars from the shower/tub.
I guess something in the soap left a film barrier.

 

[Drew99GT]

My technique is to idle the engine until enough heat comes out the vents and the fog clears. I usually only need to do this a few times a year when it gets bitterly cold.

 

[190E26FTW]

Keeping windows clean is the best idea. The Rain X anti fog stuff does not work. Save your money.

 

[RnR]

A few years back I picked up Fog Clear at Wally and used it just prior to this winter; so far so good. But I have to agree, cleanliness is also a pretty good policy.

 

[Kaie]

I use my defrost.

 

[Warstud]

Roll down the window to let the moisture out when you breath otherwise it fog up the windows.

 

[Surestick]

+1 on keeping the windows clean.
Also one thing that helps is turning the heater to cold a few minutes before parking the car so you aren't leaving it full of warm, moist air. It helps to prevent the windows being covered in ice on the inside when you get back to the car (though it's only really necessary when it's below around -15C).