A viral tip claims that keeping a glass of salt in your car is a useful trick every driver should know—sometimes even framed as advice from a police officer. But what does salt actually do inside a vehicle, and is this “hack” worth using?
Let’s break it down.
What Salt Can Do in a Car
Salt is hygroscopic, meaning it absorbs moisture from the air. Because of this property, salt can help with:
1. Reducing Foggy Windows
Moisture inside the vehicle contributes to foggy glass. Salt draws humidity from the air, which may slightly reduce interior condensation.
However:
-
It works slowly
-
It’s far less effective than products designed for moisture absorption
2. Acting as a Simple Dehumidifier
In damp climates, salt can help a bit with musty smells or humidity buildup—especially if the car is parked outside overnight. What Salt Cannot Do
1. Replace a proper defogger
Your vehicle’s HVAC system is significantly more effective. Using salt shouldn’t be your primary method.
2. Melt ice inside the car
Salt can melt ice on sidewalks—not on your windshield from the inside.
3. Prevent you from being pulled over
Some versions of this story imply you won’t fail a sobriety test or that police recommend it for visibility—this is misinformation. Salt has no effect on law enforcement procedures.
Is Salt in a Glass Safe in a Car?
A glass container is not ideal. It can:
-
Break during sudden stops
-
Spill salt everywhere
-
Draw moisture and clump, making a mess
A safer option is:
-
A plastic container with holes poked on top
-
A sock or cloth bag filled with salt or rice
-
A small commercial moisture absorber (“DampRid,” “air dehumidifier bags,” etc.)
These options are designed to avoid spills and work better.
Better Alternatives for Foggy Windows
If fog is the issue, the most reliable methods are:
-
Use your vehicle’s defrost mode
-
Turn on A/C (it removes humidity)
-
Keep rubber seals and cabin air filter clean
-
Remove wet items from the car
-
Use an anti-fog spray on the windshield
Bottom Line
Keeping salt in your car can slightly help reduce moisture, but the viral advice is exaggerated. It’s not a miracle fix, not a police-endorsed driving secret, and not nearly as effective as proper ventilation or dehumidifying products.
