That’s another viral “life hack” headline, and it’s mostly misleading or exaggerated.
What people claim
Putting a glass of salt in a car is said to:
- Remove humidity
- Stop fog on windows
- Prevent mold and bad smells
- Keep the car “dry”
What’s actually true
Salt does absorb some moisture from air (it’s hygroscopic), so in theory it can slightly reduce humidity in a very small, enclosed space.
But in a real car:
- The effect is very weak
- It works only in small, closed containers, not a ventilated vehicle
- It won’t meaningfully fix foggy windows or damp interiors
The downsides (rarely mentioned)
- Salt can spill and damage interior surfaces
- It can increase corrosion risk if moisture + salt spread onto metal parts
- It’s messy and not practical
Better, proven solutions
If your goal is moisture control in a car, these actually work:
- Silica gel desiccant packs (used in electronics packaging)
- Activated charcoal bags (for odor + moisture)
- Fixing water leaks or wet carpets
- Using the car’s air conditioning + defrost mode properly
- Keeping windows slightly open in dry weather for ventilation
Bottom line
A glass of salt in a car is a viral hack with minimal real benefit. It’s not dangerous, but it’s also not an effective solution compared to proper moisture absorbers.
If you want, I can give you a simple “no fog on windshield in winter” method that actually works fast.

