You can wash a vehicle by taking it through an automatic car wash or by hand-washing it. Hand-washing is more effective for removing dirt and film-forming residue.

You will need a nondetergent soap, such as Murphy Oil Soap. Do not use a liquid or powdered laundry detergent. Such products can harm paint. You will also need a large, soft car-washing sponge with open pores, as well as a chamois. Both items are available from an auto supply store.

Follow these steps:

1. Connect a garden hose and spray the underside of the body and the insides (wells) of fenders with heavy blasts of water to wash away road salt, which is corrosive and can cause rust.
2. Inspect the body for rust spots, especially quarter panels and fender wells. Use a penknife to scrape off rust, and spray the spot with rustproofing compound, which is sold in aerosol cans at auto supply stores. It is important to eliminate rust when it’s in a forma­tive state. If the condition is allowed to spread, an expensive repair by a professional body shop can be anticipated.
3. Park the car in shade.
4. Mix car-wash soap in a bucket of warm water to make a sudsy so­lution.
5. Wash the car from the top down, one section at a time. Start with the roof, followed by the hood, deck lid, each side, grille, and the rear panel. Using the sponge, flood the section with the soapy so­lution, pressing down to loosen grime. Before the solution has a chance to dry, spray the section with water from a garden hose. Move on to the next section.
6. After the car has been washed, spray it with water again. Then, dry it with the chamois, but first soak the chamois in water and wring it out. Start with the roof and proceed from section to section. As the chamois becomes saturated, wring it out.
7. Finally, inspect the body for tar and insect residue, which can be removed with a tar-and-bug solvent.