So, once you get the fog off (most likely outgassing as stated earlier), you need to take care of the source. The outgassing happens as the plastics oxidize, a process speeded up in sunlight. You can slow down the outgassing by using the correct plastic treatment i.e. 303 I had absolutely no window fogging since treating the interior with 303 over a year ago.

i used to get that all the time and this salution does work better than anything else.

I did the newspaper trick tonight (with windex), wow!! it really works easy. One quick wipe and not a single streak, I change my mind, I am into windows now.

You forget he lives in Flordia where it rains all the time and theHumidity is high.

I live near the beach and have to clean constently the inside window. It's the salt air.

My window fogs ALL THE TIME, i put Rainx anti fog on and omg it was the worst thing i ever did to my car. I put it on about 2 weeks ago i still can't get it off! i dunno what to do!!!!!!!!

Maybe you should get your eyes checked for astigmatism. Seriously. I know people with astigmatism who feel like that all the time when driving at night; regardless of how clean their windshields are.

The best remedy is just plain old vinager and paper towels. Then use a newspaper to make it sparkling clear! Cost is about $.85 Then you can have a salad afterwards....:D

Personally.... I like Glass Plus. I have no idea what is in that stuff but it cleans just about anything.

If the problem is oil on the outside of the windshield it is probably just road goo. The best way to get rid of it is probably to was the window with something like Dawn Dishwashing Liquid. Just keep in mind that it will also take the wax off of your car. So be prepared to rewax the car as well.

Between waxings I use Eagle One's Wax-as-you-Dry stuff. The nice thing is that this stuff goes right on the windows as well as the body. I have found that not only do my wipers perform better since the water beads on the windows, but it is easier to clean now.

oil/plasticizer
 

It is oil/plasticizer film. Hard to get rid of. Armorall and UV protectants and plastics emit these and it coats the windows. If you have tinted windows do not use amonia sp .... Check at some of the auto stores for some heavy duty stuff (windex my fav. w/o tint) and clean and clean again. The newspaper trick works well w/o tinted windows.

use Stoner's invisible glass cleaner, once you have it very clean use Zaino Z6 detail spray (very light amount, a little goes a long way) with a microfiber towel inside and out, this combo rocks

newspaper/vinegar is an old house window cleaning combo that works very well EXCEPT vinegar is an acid and may cause issueslongterm if you get it into areas inside a car and newspaper can scratch glass if you're not careful

Rain X removal
 

Take a clean towel and dampen it. Go over the Rain X and it should come off.

Damn, and you're already over 960, just a couple days later? I must be way behind on my posts!

If that's true, and it makes sense that it is, then that's interesting information to know. I've known about the newspaper trick for a while but never took the time to understand why. The things you learn sometimes!

Yeah mine is sooo fucked up rainx sucks! It has gotten worst.

I think the rain-x for the outside works great. The only thing is after a few applications it builds up and does the opposite of what its supposed to do. Rubbing your window down with rubbing alcohol will give you a clean slate for rain-x.

Oh wow windex works!!!

The best thing is denatured alcohol and a terry cloth rag that has not been cleaned with laundry softener or dryer sheets. It removes EVERYTHING. Inside and out. I always clean the outside before replacing wipers - make a huge difference. Be careful around seals though as it can dry them up with too much contact.