[3.2 CAB]

It probably was not a "spray can". the PO more than likely had the car detailed before selling, and the is what is left of the glazing or buffing compound, they squirt it on in a puddle or lines all over the place, then hit it with the buffer, it slings that crap everywhere. Some of it does not really dry to white until some time has past. Like Erakad said "toothbrushes" will get it off, but it is a PITA, but you don't risk damaging the paint. As far as the black goes, the products mentioned before will work fine, you just have to take your time and be carefull, sometimes have black dye, and they will leave black where you don't want black. It will stain open paint. My 2cents$