My solution is a felt CHALK BOARD ERASER. With a chalk eraser, kept in the car, you can quickly erase the dew off of your vehicle’s windows in seconds. The eraser dries out during the day and is ready again for the next days use, if needed. The eraser is small and compact (hand sized), and can fit easily in any of the compartments (ex. cup holder or glove box) in the front seat of your automobile.
Pick one up at your local arts and craft, or toy store. I’ve kept one in my car for years, and it is always ready if dew happens to form on my car’s windows. Happy Erasing!