Given how much salt is spread on our nation's roads in winter, it's no surprise that corrosion problems become an issue this time of year.

"Typically, people will see the rust that appears on a car's rear quarter panels," says Steven Fisco, president and owner of Fisco Auto Body Inc., in Franklin, Wis. "But doors are actually the worst because they rot on the inside, and you don't see that damage until it gets really bad ... it will get started and grow in those places where you have two layers of metal pinched or welded together."

The cost of proper repairs will vary depending on the extent of the damage and where it is located.

"If it's on the exterior surface of the car, it's going to require much more care and work than if it is on the inside of a doorjamb, where the finish work doesn't have to be so perfect," says Fisco, adding that repairing rust damage on a door will typically cost around $750. Repairing rust damage on other body panels can run $350 per panel.

There's no escaping winter's slush and road salt; the best defense is to wash your car frequently.