Fog can form on any type of glass when the air on one side of the glass is colder than the air on the other side. Glass car windows commonly fog in the winter when it is cold outside and the heat is turned on the inside the car. Cleaning the fog off the window can be done quickly with a paper towel, but that will not stop the fog from coming back. It is important to clean the glass window so that the fog does not return.
Wipe away the current fog with a paper towel. The fog is just droplets of water so it will easily be absorbed with a paper towel.
Squirt some baby shampoo on a clean rag.
Wipe a thin layer of it across your window glass. Cover every area you want to keep free of fog.
Rinse the glass off with a clean wet rag. There will be enough shampoo residue left behind to stop the fog from forming on the glass.
A 50/50 vinegar water solution can also be used to clean the foggy glass windows. You can purchase a chemical defogger to apply to your glass to prevent fog from forming.