Originally Posted by chuck65
I use detailing spray for light dust or pollen but never for encrusted dirt. You have to evaluate if the abrasive possibility of the dirt or dust you want to remove. If your in doubt, wash it. My Crossfire is only driven on dry days and is always garaged so I use Meguires Ultimate spray quite often, and don't wash it very often.
I think Chuck65 is right on the money. I use Ultimate Detailer too and only to bring the pop back to the wax-never to remove anything more than light dust and pollen.