Dot 3 Brake Fluid
wet a rag pour a can of coke on it and then rub it on the cement. then get a stiff wire brush and then rrub it against the cement
The first question is what caused the black marks? Rubber tires leaned agains or piled on the car? Usually a carefull rub down with a cleaner like Acrosol or brake clean wil take that of. CAUTION these chemicals can damage some paints, BE gentle. Tree sap, good car wash soap will clean this. Etching in the paint because moss has grown in the cracks and cranies. Good soap followed by a light cut polish will make for the best result.
spray WD-40 on the marks and they will come off not affecting the paint!
A Car Painter
A rag with a bit of petrol or otehr orgaanic solvent should do well enough,
Try using polishing compound. Your local auto parts store should carry it.
skid marks
Car Paints or car sprays help =) science
It varies from car to car, most manufacturers have marks showing where the lift points are. The marks are near the wheels on the bottom outside edges of the car.
Removing accumulated or long ingained dirt, sooth or filth on car paints
wash it with vinegar
Well, most metallic paints are actually car paints. So it will be very hard and expensive to do it to dry wall.