I have tried a number of methods for cleaning the filmy build-up off the inside of my car’s windshield. Window cleaner (a variety); vinegar; newsprint, etc. No matter what I try there are always some missed patches or streaks that show up in the bright sun.
If you are good at this, tell me your secrets. Off the shelf product? Home-made solution? What implements do you use to reach the tight spots?
A video from this thread..
First you clean it with a dry microfiber towel. Then use a Magic Eraser, which gets rid of the filmy buildup. Finally, use a streak-free glass cleaner (he uses Zep) to get it completely clean. IME it really works, especially for the film.
In terms of getting to the corners & tight spots, grab a nearby 10 year old with small hands to clean the edges for you.
Then clean the rest of the windshield where the 10yo put his/her grubby hands. 
Thanks. I hadn’t thought of using a Magic Eraser but I will give it a try.
I’ve had pretty good results from just using the stuff at the gas station. Clean the outside of the window with the squeegee, then use the towels on the inside.
You can also use one of these tools to help:
AutoFiber – highly rated by pro detailers, but pricey:
Invisible Glass Tool:
Coincidentally, I just watched this YouTube video mere moments ago. The key seems to be a silicone squeegee with no metal parts.
Notice in the squeege method that a bunch of shit drips off the squeege as you are pulling it across the glass. Put a large towel (or 2) on the dash to catch these and prevent dirty shit water from dropping into your defrost vents and festering in there (and/or relaunching grime onto the windhsield the next time you turn them on).
And don’t spray directly onto the windshield like the guy did at the beginning of the video, that is a good way to get little spotty chemical stains all over the dash if you don’t get them properly rinsed and wiped up, especially if the dash is hot. Wet the towel and use it to apply the cleaner to the surface…
The big challenge is the offgassing plastics in the car which leave a film. That film can be incredibly hard to remove, whether you’re using dish soap, rubbing alcohol, glass cleaner, or a razor blade. Sometimes all it does is smear around. Using some bon-ami powder turned into a paste can sometimes cut through it, but you need to rinse it off well, and definitely protect your dash with a towel when using, because it is an abrasive (just not one that will scratch glass).
Good luck!
The Magic Eraser worked really well.
What do you think the film is?
When I bought my father-in-law’s pickup no matter what type of conventional glass cleaner, vinegar, household cleaners I used there always ways a haze driving into the sun.
He was a smoker and I was sure it was some sort of film from his cigarette smoke. Finally tried lacquer thinner and that took it off. As mentioned before I should have put something on the dash as the drips left spots on the dash.
If only Car Talk was still on the air…
I have heard it’s a combination of plastic gases and human expulsions.
I’ve heard more specifically that this film includes dioctyl phthalate (DOP), an oil often used to plasticize polyvinyl chloride. Without plasticizer, PVC is brittle. With plenty of plasticizer, it becomes vinyl, which gets used all over car interiors.
Things that are good at dissolving DOP will remove at least that part of the grime, but will unfortunately also dissolve or at least permanently mark vinyl dashboards if they drip.
Yeah. You need dashboard solvent to get the dashboard fumes off the windshield. Just don’t spill the dashboard solvent on the … you know … dashboard. 
I use one of those cheap “reacher” arms with a microfiber pad. To keep the pad as clean as possible, I spray a square of blue shop towel (paper) with “Perfect Glass” cleaner and drape it over the microfiber pad and use that. I try to time my cleaning so that the sun is at a low, oblique angle, which shows streaks really well. It takes several passes to get it perfectly clean.
FWIW, this works well for the windows in our house. The sunlight thing is really important, because it’s easy to get a window looking really clean, and then have the setting sun come thorough it and highlight streaks everywhere!
Kinda like a disintegrating pistol, eh?
Acetone might work. I’ve used it to take crap off the exterior of the windshield that other products couldn’t touch.
When trying out different methods, make sure to give them time to fully dry before evaluating them. I’ve found just an alcohol-based cleaner and microfibre towel to work fine, but it can look at bit streaky at first until I leave it alone for a minute.
I’m good at avoiding touching the inside of the windshield and hadn’t picked up any big rub marks during the last few years. But it still gets subtly dirty and the low morning sun was hitting the film which, while even, had reached ‘dazzling hazard’ intensity. I cleaned the windshield yesterday and I’m really really happy with it and document my findings below.
After reading this thread and elsewhere, I acquired: reaching dealie* w microfiber cloth heads, Invisible Glass cleaner, magic eraser(ME), Swiffer sheet, microfiber rags.
*reacher I used
https://www.amazon.com/dp/B0BN4G64ZN
Another thing visible in the low sun were the hundreds of miles (estimated) of spider webs crisscrossing the glass superhighway. I started by giving the whole thing a wipe with a dry Swiffer sheet. The was a cinch after tucking the sheet in the elastic on the cloth head on the reacher. There wasn’t much grime or discoloration on the stark white sheet after the wipe.
Next, I sprayed one of the microfiber reacher heads and basically got the whole glass surface wiped wet, though maybe not all at the same time. A little scrubbing. After this, I sprayed an ME pretty wet and started scrubbing areas about a handspan at a time. Respray the ME as needed to keep it wet. This was awkward, contorting, vigorous work and I’m pretty sore today.
I’d put down some newspaper which did catch a drip here and there. It was also useful masking where the bottom of the glass converged with the top of the dashboard. I really wanted to avoid letting the ME or reacher cloth contact the dash and disturb the, um, patina.
After the ME, I washed and washed again using two microfiber reacher cloths. The first one was used before and after the ME steps and is very visibly dirty and discolored. After the second, I let it all dry out for 15 minutes or so and the glass was already looking amazing but there were some sort of lens flare-y swirl marks that would catch the light sometimes. Through trial and error, all the glass needed was a final buffing with a dry microfiber in a few areas.
The glass really does look great. It was overcast this morning so I didn’t get that telltale morning light but I’ll bet it’s going to be fine. The ME scrubbing was very hard work but I’m certain it performed the largest part of the cleaning. The MEs also make an otherworldly squeal when dragged across glass just right. The reaching device is very useful and easily worth the money. I plan on hand washing the microfiber heads but replacements are under a dollar each, pretty much disposable.
But ya, cleaning glass is a pain but worth it. Get a reacher. Use an eraser. Clean on a sunny day.
Invisible Glass is the best at removing the film from the dashboard off gasing. I’ve used both the tool linked to up thread and microfiber cloths with equal success.