You can spray WD40 and wipe on mirrors to prevent fogged up during showers and baths.
By mlholm812 from Parma, OH
You can also use a cheap shave cream, clean the window with it just like you would a cleaning spray. Might be cheaper than WD40.
Does this work in car windows?
Well I know everybody loves to have a hot shower or bath. And when you get out you like to look in the mirror, but you can't because it is all steamed up.
Now my favorite thing to do to prevent that is to put Colgate shaving cream on my mirror. It shines and prevents the steam from fogging it up. Just be sure to rub it in well and don't put too much. If you do, it will leave white streaks and it will be embarrassing. Now you will have to do this every 3 - 4 weeks or so but I do promise you it is worth it.
By Sarah from Watauga, TX
To make a homemade anti-fogging glass cleaner try any of the following: