I use Meguiars Quick Detailing spray on my black raodster after washing but it seems that when I wipe it off it leaves trace dullish areas that I can't seem to wipe off. You have to look real close to see these areas. Am I doing something wrong? Is it just because the car is black?

I have switched to Meguiars NXT spray wax for my detailing after washing. It leaves a haze but it wipes off easily with a polishing cloth and leaves a nice finish and doesn't seem to take much more time.