First off Andy M when I wash a car it is inside a garage. No chance of anything being blown on the car. If you use a squeegee correctly you will have a wall of water in front of it as you pull it across the paint. This wall of water will push any grit that might still be on the paint (if you still have dirt on the car after a good wash...you are not washing the car right) It works for me.
Ping Golf Club demo tech