I have the same thing. It is neither on the inside or the outside. Mine isn't coming out.

You've not said if the glass is clear. However, I have used a product available at Home Depot called Shower, Tub and Tile cleaner put out by ZEP. Follow the instructions, and for sure test on a small corner first. I use a white abrasive pad with this on stubborn marks. and found it may take more than one use. For sure, test on inconspicuous area first - it has a harsh odor as well!!

Is this a double pane insulated glass door? Could be the seal is failing and the cloudiness you see is inside the space between panes. Sometimes the first clue is just a bit of spottiness that doesn't clean up when the outsides are cleaned....Just a thought.

To answer the questions posed....it is clear glass....it is a sliding glass door....and it is NOT double pane insulated glass.

Could it be that there is a film coating and it's actually coming off rather than something being on it?

rob333,

It does not appear to be a coating. There is no bubbling up nor pealing of any type. It just looks like something has dried on it. It isn't actually the shape of water drops, but when you look at it it looks to me like liquid has dried on it. I just now took a look and I scraped on each side of the door. The door must be double pane and the spots look like they must be between the glass.