Best way to de-fog the windshield?

This sort of stopped me in my tracks this morning. A headline which read, "Using Shaving Cream to clear up that foggy windshield."

My first thought was how hard it would be to get that cream off after the window cleared of fog or frost. Can be used inside and outside on the window. Some people swear by this method, but I doubt I'll try it. My method is to get the car running before we have to leave with the defroster running.

I have used a vehicle ice melt spray in frozen door locks and doors themselves at times.