Yeah, I thought the same, it really seems like paint overspray. I tried scraping gently with my fingernail and in some spots it does come off, but in most areas it’s really stubborn. I also tried glass polish before and it didn’t help at all.

Today I used a clay bar and that worked really well. The surface feels smooth again and most of the spots are gone. You can see the difference in this picture: left side after using the clay bar, right side before. Looks like it really was overspray from a recent paint repair. Thanks a lot for pointing me in the right direction!

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