It seems some motorists are only now realizing what a little-known button on their dash really means.
Experts say knowing the function could help save your life.
The button is marked with an icon that shows a rectangle with three wavy lines pointing upwards.
It seems some drivers don’t even know what it does – it fogs up the rear window.
A push of a button is all it takes to turn it on.
Most models then turn off automatically once the window is cleared. However, some older versions require you to press the key again to turn off the window once the window is cleared.
The feature was demonstrated in a short TikTok video by Mike Hinton Driving School, known as “@mrdriveruk”, which has around 31,500 followers.
Similar advice was shared by social media user @drivingtestsuccess.
The second video also explained how to tell the difference between the front and rear demister buttons, with the front one having an oblique icon instead of a rectangular icon.
RAC experts advise drivers to always wet their windows before driving, as this could reduce visibility and lead to illegal driving.
The Automobile Association warns you not to “drive until all glass surfaces of your car are clear”. It is dangerous and illegal if visibility is compromised.”
It is recommended that the vehicle’s air conditioning, if equipped, be used in conjunction with the heater.
The RAC said: “Hot air dries the glass a little through evaporation, but the air then cools and condenses again on the glass. So make sure the air conditioning is on to keep the atmosphere inside dry.”
If your car doesn’t have air conditioning, you should actually open the windows to clear the panes faster.
According to the RAC: “This helps because the dry, cold air from outside can help reduce the amount of water vapor inside the car, thus preventing window fogging.”
The experts also revealed a nifty trick to cleaning your windshield — with shaving cream.
All you have to do is take a clean towel and then put a dollop of shaving cream on it.
Then wipe the windshield with the towel, making sure to spread the shaving cream over the entire surface.
Next, take another clean towel and wipe off the shaving foam completely.
However, it warned: “This protective barrier will not last forever and may need to be repeated periodically, but a windshield cleaned with shaving cream fogs up less.”