TIP: Always spray your vehicle down with high pressure from your nozzle. This will remove most of the heavy debris before applying soap.
For the safest application, use a spray nozzle that allows you to blend and spray soap and water simultaneously. This will help with providing a layer of viscosity on the surface of the paint and reduce possible scratches from debris on the car.
Try rinsing your car without the nozzle. Remove the nozzle and let the water run from the top, down and "chase" the soap away. This will promote the sheeting action rinse and reduce water spots!!