Maintaining a black (or any dark colored) car takes a lot of work. If your car stays outside and not in a garage you will find yourself washing it more frequently to keep it looking fresh. There are specific products (car wash, wax, etc.) for black (dark colored) cars that you can purchase... check some of the upscale detailing websites for those. For removing light dust/pollen there is a product called California Duster that you can use to remove it, however it shouldn't be used to remove dirt/grime or if the car has been wet (rain, snow, dew, frost, etc.) as it could scratch the surface removing the dust/pollen after it has gotten wet. As long as you are using a quality car wash and waxing the car periodically (I wax mine every 4 months) you shouldn't need to apply anything after washing. There are some videos on YouTube with tips/tricks on how to keep a black car looking good.