Small black stains on paint

Hello, I took over a new smart 450 a few days ago and the previous owner has dealt terribly with it… The car is from 2006 and at the time the smart has perhaps seen a washing machine from the inside a maximum of 5 times. And from vacuum cleaner he has heard nothing until today. Since I want to take better care of the car I was today at the conditioner with which I made an appointment a week ago which carried out an outdoor and indoor cleaning. I had Tuesday evening auc h once the car so to speak “washed up” to solve the dirt in the hope to get everything away… Unfortunately, it was not like that. After I got the car back from the conditioner today is unfortunately still a lot of dirt on the vehicle.My problem is that there are small black spots on the glass roof in a few places of the paint and (this bothers in particular) on the glass roof and they just don’t want to disappear, no matter how often I wash the car. said it would be necessary to clean the paint with polishing so that I can get rid of the dirt and demand 100-120€ for it, because I do not want to spend so much money and if then rather put in cleaning products and accessories to do it myself then I would like to make sure what you say about it… Whether I get rid of these stains or I have to repaint the car to get rid of the dirt. My boss (he knows quite well about everything around the car) also said paint cleaning and referred mi After looking at this, I would now buy the Meguiars Quick Clay Kit and try to get rid of these little gems… What do you say? Can you explain to a car new and first-owner what I can do? I would be very pleased with the answers, I would like to clean the car from scratch and then wash regularly so that it doesn’t happen again. Thank you very much! – Daniel P.S.: When “pre-washing” has If I scratched the paint very easily in some places, can I get it out with polishing?