It really depends on how dirty the car is. My Crossfire sits in my garage a good bit of time between drives, so a lot of times it's just dusty and needs a good wipe down. If it's a little bit dirty I sue Griot's Garage waterless wash + their waterless wash microfibers, which are a bit bigger and plusher than your standard issue microfiber. But if the car is full-on dirty, I prefer to use the ol' soap and bucket method as I don't want to grind dirt into the paint/clearcoat with a microfiber towel.