Keeping cars clean and shinny in countries like USA, CANADA, UK, GERMANY and many other is very much easy because of there atmosphere and clean air, but to keep car shinny, neat and clean in KARACHI is not easy specially Black color cars, but as all my friends gave there own opinions about keeping black car shinny, my opinion is wash them after every 2 days and polish them as well, but try to leave that polish on it for about 1 hour and use a good polish and check the result, what important is your hand, how hardly you rub the body....All is on you...work hard and get better result.
You can see in first pic that without polish how the front body looks like and after polish how the rear part is looking although my car is very old it would shine more if its a new model car, I love to own a black color car.