Aiming the jet upwards can rub grit and grim over the paint and scratch it.
Aiming the jet upwards will not loosen and soften the dirt from the top of the car.
Aiming the jet upwards around windows may cause water to dribble into the car.
Aiming the jet upwards will make water spots and the car will need to be rewashed.
To prevent paint and interior upholstery from being faded by the sun.
To prevent the person washing the car from getting a nasty sunburn.
To prevent premature drying which can leave splotches on the paint.
Direct sunlight prevents the car-wash solution from bonding with dirt.
Sponge or mitt
Short wire brush
Hose off the wheels
If the car is going to be inspected
If the car has been exposed to salt
Before washing the bottom of the car
After all other areas have been washed