I use a duster if the car is clean. I would say for the first couple days or so after a wash, it's cool to use. don't drive it for 2 weeks and then bust out the duster, the debris will be too thick and can streak the paint with fine scratches. If you wash it, let it sit at a car show, and want to wipe it off half way through the day, your good to go, but dont wash it for the car show this week, and then dust it off next week after a week of driving. Or, test it out on the roof or something. Just dont "test" it on the hood! I say use it. Also, keep the duster clean. If it gets nasty, it doesn't matter how clean the car is, you could end up with problems.