As we all know, black cars are a blessing and a curse. Keeping them looking great is a bear!
I've found a system (below) that eclipses anything I've ever used. I've only used it on clear-coated cars and it does a spectacular job. On top of that, my car stays "clean-Looking" longer than ever before.
The system consists of Liquid Lustre's Acrylionic LXR (www.lustrelab.com), Liquid Glass's Car Wash and Liquid Glass Coating. (www.liquidglass.com)
Dilute 2-3 Tablespoons of LXR and Liquid Glass Car Wash in a gallon of water. This is your hand washing solution. Get a micro-fiber mitt and carefully caress/clean all surfaces of your car, including all glass and wheels.
Get a sidewalk blower and blow the residual water off the car and quickly dry with 100% cotton towels. NO Chamois.
Then apply a coat of Liquid Glass to every surface, including glass and wheels, headlights, etc. Do this a section at a time and buff it off after it haze drys. Do your entire car in the shade or a garage. Turn your towels often as the Liquid Glass "gums up" the towel.
Then park your car in the sun for a 1/2 day. The Sun's UV rays will harden the Liquid Glass and now you have a nearly impervious surface that will protect your car and repel dirt.
Give your car a second or third coat every 30 days up to 3 coats.
Reapply every year when inspired.
I've followed this system, sharing only with my important friends, for several years. The results are much better than the bottles of Mother and Mequiar's sittling in my garage. In fact, I am surprised that these two giants haven't bothered to buy Liquid Lustre or Liquid Glass.
Let us all know of your findings. As my Dad used to say, "Never drive a dirty car out in public."