Auto body repair & detailing: car paint and rain, acid rain, overspray

Question
I didn't know who to ask about this and you may not know the answer but I'll try (this isn't a homework question, I'm 63 yrs. old)...
My new car sits out in the sun and I noticed there was a yellow squiggle mark on the paint. I sometimes see small yellow debris from trees  or whatever else that floats in the air and lands on my car and I brush it away. This time, the debris was completely gone, but the yellow imprint seemed to almost be baked into the paint, I couldn't even feel it with my fingernail. I used soap and water on a rag and it wouldn't come off, no effect. I came out the next morning after it rained and it was gone! I'm stupified, because as I said, it was as if it was baked into the paint. Do you know if there is there something in rain (acid?) that somehow dissolved or got rid of what I described that was on or in the paint?  Thanks

Answer
Hi Lee,

Usually acid rain causes more problems than it helps. Typically it etches paint surface and it will feel rough to the touch. My guess is that it was pollen from an evergreen type tree. It can sometimes be very tough to remove. I would suggest something like an overspray clay to remove it. Overspray clay will remove stuff like stuck on bugs, bird droppings, water spots, pollen, and even paint overspray without damaging the surface.