You have to be kidding me, an entire article on washing a car? Yes, and believe it or not, very few people know how to do it correctly! Basically half the battle is just being aware of the potential problems that can happen when one washes their car improperly.  Here are a few dos and dont's to be aware of:
Don't wash your car when it's baking hot - The heat causes the soap and water to dry rapidly which will leave streaks on the paint and can make the whole washing process much harder. When the weather is going to be hot, first thing in the morning is a good time to wash your car, or when the car is parked in the shade, the sheet metal will be much cooler.
Do hose off the vehicle before washing -Â A thorough pre-rinse will not only help cool off the sheetmetal when its hot outside, it will also loosen up loose dirt, leaves, or other debris that could scratch the paint..
Do wash your car ASAP when stuff has landing on the paint - Do a full wash as soon as you see things like bird droppings, dead bugs, or other obvious contaminants on the paint surface. Bird droppings, in particular, have a high acidity that if left on the paint for any length of time can eat into the clear coat.
Don't use a household detergent to wash your car - This is one of the most common mistakes. Dish soap, laundry soap, and household cleaners are often too harsh to use on a car's paint. They can strip off the protective wax coating and possibly dull the paint's finish. A dedicated carwash formula, on the other hand, is formulated with a milder soap that doesn't affect the protective coating. It's worth the extra $5 to get the right carwash formula.
Don't use abrasive materials to wash with - Whether washing or drying, never use a rough cloth or other material with a surface that can scratch. A large sponge works well, or many professional detailers prefer to use a lamb's-wool mitt. Â There's a reason for this. The thick nap of the lamb's wool allows loose particles to be worked up into the wool.
Do use a bug-and-tar remover to finish the job - Mild carwash formulas often aren't strong enough to remove road tar, grease, or similar residues. Â For this, a strong bug-and-tar remover is a good idea.
Do use a chamois, terry towel, or synthetic chamois to dry the vehicle - Many professional detailing shops use terry towels. Â A natural chamois works well too, but requires more maintenance. It can't be stored wet and becomes stiff when dry, needing to be remoistened before use.Â