Your car's underbody fights an ongoing battle against corrosion. Just a few simple steps can help keep it rust-free.

Thoroughly flush road-salt residue with a garden hose. Spray especially well inside wheel wells and on the underbody, where accumulated mud and leaves act as moisture traps, creating ideal conditions for rust. Use a stiff brush to remove any clinging bits that your hose misses. While you're there, check for loose or missing splash guards or inner fender panels. These must be reattached or replaced.

Many vehicle doors have drain holes that can become plugged. Use a thin wire or pipe cleaner to scrape them free. Clogging can create a corrosion colony inside that may rust through quicker than exposed parts on the car's underside.

Once each month, get under your car and inspect for clogged drain holes and missing plugs. Loose undercoating can provide a place for salt and mud to collect in contact with the metal panels. Use a putty knife to pry loose any corroded or cracked undercoating, then wire-brush and clean with solvent. Respray with spray-can undercoating, which you can find at the auto parts store.

Similarly, inspect suspension components like the top of control arms for pockets of mud and road debris. Remove any of this material and keep the areas painted.