“Put a Glass of Salt in Your Car” — Does This Actually Work?
This viral car hack has a little science behind it, but it’s greatly overstated.
💧 The idea
Salt is hygroscopic, meaning it can attract and retain moisture. In sufficiently humid conditions, sodium chloride can take up moisture from the air.
That’s why some people suggest putting a container of salt inside a car to reduce condensation, musty odors or window fogging.
🚗 But there’s an important catch
A glass of ordinary table salt is not a particularly effective car dehumidifier. Sodium chloride generally doesn’t absorb substantial moisture from ordinary indoor air until humidity is quite high. Purpose-made moisture absorbers typically use much more hygroscopic materials, such as calcium chloride.
And there’s a potentially counterproductive issue: salt and moisture together can accelerate corrosion of metal. So you definitely don’t want loose or spilled salt sitting on your vehicle’s metal surfaces.
✅ If your car has excessive condensation
Rather than relying on a glass of salt:
- Check for wet carpets, leaks or blocked drains.
- Remove wet mats and allow the interior to dry.
- Use the car’s air conditioning, including during cooler weather, to help remove moisture.
- A purpose-designed car moisture absorber is a more sensible option if humidity remains a problem.
- If windows repeatedly fog up despite these measures, investigate the source of the moisture.
