This type of salt, with its drying agents, is effective in small enclosed spaces like cabinets or drawers. But what does this have to do with cars? The Car Hack Recommended by Mechanics When temperatures drop, car problems such as engine or battery failure become more common. Moisture buildup inside the car, especially on glass surfaces, can be a real nuisance. Moisture inside a car in winter can lead to component deterioration and mold growth. .