Direct airflow toward the windshield and follow the instructions recommended for your vehicle. In many vehicles, the air-conditioning system can help remove moisture from cabin air even when you are using warm air.
Modern climate-control systems are specifically designed to deal with this situation far more rapidly than a passive container of salt.
Fresh Air Can Help
Continuously recirculating humid cabin air can sometimes make condensation more persistent.
When conditions allow, bringing in drier outside air can help remove accumulated moisture.
The correct climate-control setting varies with the vehicle and weather, but if windows keep fogging while recirculation is active, switching to fresh-air mode is worth trying.
Keep the Inside of the Windshield Clean
Even if humidity is the underlying cause, dirty glass can make fogging appear worse.
Over time, the inside of a windshield develops a thin film from dust, fingerprints, interior materials, cleaning products, and airborne residues. Moisture can form across this contaminated surface.
