Guys about 3 days back I had an incident. My dads car and my car were parked in our porch. Bahria town people were spray painting the street lights outside on our street. It was extremely windy because of which silvery sprayed particles fell on both our cars...and both vehicles are completely covered in dust like spray 
Now its not coming off. I tried Scratch out with Meg's micro fiber and even megs wax. Also tried wd-40 but its not coming off. Its like grainy sand particles.
What should I do. Should I do full body compound polish (which products?).
Or should I use thinner (is it safe on car paint).
or any megs product helpful (megs rubbing compound/cleaning wax/clay kit)..
need help guys. The vehicles are both metallic blue paint. 2D saloon and land cruiser prado.