There are a few different ways that you can defog your car mirrors. The most common way is to use a defogging solution. You can either buy a ready-made solution from a store, or you can make your own by mixing water and vinegar in equal parts. Another option is to use rubbing alcohol. Simply pour some onto a clean cloth and wipe it over the surface of the mirror. If you don't have any of these solutions on hand, you can also use hot water. Pour it onto a clean cloth and wipe it over the surface of the mirror. The heat will help to evaporate any moisture that is causing the fogging.