Looks like a chemical stain.

 

to clarify, windex is fine. it's the windex with ammonia, or any other window cleaner with ammonia that you want to avoid. windex does make a cleaner that does not have ammonia in it. and to further drill it down. if you have a denim bike, windex with ammonia used to be the hd recommended cleaner before they came out with their version of denim bike cleaner.

so use windex with ammonia on the bike, and windex without ammonia on the shield...

 

Seen that a number of times __ Alot of them was just simply age

WP

 

Tape wil not pull tint off of a prescription eyeglass lens. We use molecular catalytic dyes that impregnate the surface of the lens. They can fade, but will not peel.
This person's windshield looks like bleach or brake fluid or something caustic got splashed on it.

 

That might not be the best advise!
I tried all kinds of things, including Plexus (which after a while left a rainbow effect.)

After getting frustrated I checked what my windshield is made of, and went to the manufacture of that material to see what they recommend.
My OEM windshield material manufacturer recommends the Original Windex (with ammonia-D)

Scratch is correct, never use anything with regular ammonia in it, it will etch the damn windshield, but whatever ammonia-D is, it is not the same.
I have been using it for years now and except for all the dings in it, the windshield still looks like new.
.

 

I use sprayway glass cleaner on mine for the last couple years. Works great, no ammonia.

 

I don't use any thing but Adams detail spray on my windshield to clean it.