Here’s a detailed explanation:
Why do people keep salt in a car?
The main idea is that salt absorbs moisture from the air. Some people believe that placing a glass or container of salt inside the car can help:
- Reduce moisture inside the cabin.
- Prevent fogging on windows.
- Reduce musty odours.
- Minimise condensation during cold or humid weather.
However, the effect is generally limited because ordinary table salt is not nearly as effective at absorbing moisture as commercial desiccants like silica gel or calcium chloride.
Potential Benefits
1. Helps reduce condensation
If your car often has moisture inside, salt may absorb a small amount of water vapour, which could slightly reduce window condensation.
2. May reduce unpleasant smells
By lowering moisture levels a little, it may help discourage mould and mildew, which can cause bad odours.
3. Low-cost option
Salt is inexpensive and readily available in most homes.
Limitations
There are several reasons this isn’t considered a reliable solution:
- Salt absorbs only a limited amount of moisture.
- An open glass can spill while driving.
- Spilled salt can attract moisture and may contribute to corrosion if it contacts exposed metal.
- It won’t fix the underlying cause of excess moisture, such as leaking door seals, blocked sunroof drains, wet carpets, or a faulty air-conditioning system.
Better Alternatives
If condensation is a frequent problem, consider:
- Using reusable moisture absorbers designed for vehicles.
- Keeping the interior clean and dry.
- Removing wet floor mats.
- Running the air conditioner to remove humidity.
- Using the fresh-air setting instead of recirculation when appropriate.
- Repairing any water leaks.
Other Uses of Salt for Drivers
Salt can also be useful outside the car:
- Sprinkle it on icy patches to improve traction.
- Mix it with sand or cat litter for better grip if a vehicle becomes stuck on snow or ice.
- It can help melt thin layers of ice, although rock salt is more effective than table salt.
Is it safe?
If you choose to keep salt in your car:
- Use a sealed, breathable moisture-absorbing container rather than an open glass.
- Place it securely so it cannot tip over while driving.
- Replace the salt if it becomes damp or clumps together.
Final Verdict
Keeping an open glass of salt in your car is not an essential or officially recommended driving tip. While salt can absorb a small amount of moisture and may slightly reduce condensation, its effectiveness is modest. If your car regularly develops foggy windows or excess moisture, a purpose-made moisture absorber and addressing the source of the moisture are more effective and safer solutions.