Windows sides tint yellow after wash

Window side turned a tint yellow. Why? Oxidation?

one restore, or oxalic acid should fix that.

Thank you bro

What is that from

Cheap vinyl from a batch in the 90’s. Usually a day in the sun makes it go away

Had the same issue last fall. Not vinyl but aluminum trim. Turned the exact same color. I bought BARC to see if I could fix the issue. When I returned to the house three days later, the color was gone. Everything looked good. Not sure the cause but glad it self resolved. Not sure if it was the sun or rain. Hope you have the same luck!

It’s the UV from the sun that turns them white again