If you've ever seen a car for sale whose undercarriage looked like a solid block of rust, it's likely that the car was a casualty of road salt. Road salt greatly accelerates rust formation because of electrolysis—the free ions in road salt act as catalysts that cause rust to form much more quickly than it otherwise would. Older cars would often only last a few winters before they were rusted to the point of mechanical failure. Thankfully, car manufacturers have made modern cars more resistant to rust and road salt.

However, there are still a few things you need to do in order to completely eliminate the risk of winter rust. Read on to learn three things you should be doing during the snow season to prevent road salt from affecting your car.

1. Wash Your Car Regularly to Prevent Road Salt From Sitting on the Exterior

The clear coat on modern cars is excellent at preventing rust, even when it's covered in road salt. However, even the best clear coat will eventually succumb to road salt if it isn't washed off promptly. When the city's applying salt to the roads, make sure you're taking your car to a full-body car wash every few days in order to wash off all of the accumulated road salt.

Of course, your car's paint job can't protect you if it doesn't exist. During the winter, you'll need to check your car's body regularly to look for any chips in the paint. If you can ever see bare metal, you'll need to paint over it. Wash the area thoroughly, let it dry completely and then apply automotive primer and paint. It doesn't need to look perfect—all you need to do is to have a layer of paint over the metal for rust protection.

2. Stay Away From Icy Sludge Puddles

Cloudy gray snow sludge is a common sight on the roadside during winter. The sun starts melting the snow, which gets trapped in low-lying areas by larger snowdrifts, resulting in appreciable puddles forming on the side of the road.

These puddles are the biggest danger to your car's frame during the winter. They contain a substantial amount of road salt, which gets picked up by the melting snow runoff and concentrates in the puddles. This is in addition to other chemicals that collect on the road or in parking lots like motor oil.

If you're ever forced to drive through a puddle at high speeds, you'll splash up a significant amount of the sludge onto your car's body. Make sure you take your car to a car wash as soon as possible in order to wash it off—you'll minimize your car's chances of developing rust.

3. Apply Rust Inhibitor Spray to Your Car's Undercarriage

Modern cars have a rubberized coating applied to the undercarriage when they're manufactured in order to provide rust protection. The coating is quite effective, but it tends to have poor longevity. Small stones or other road debris that strike your car's undercarriage can rip off small pieces of the coating, leaving your undercarriage vulnerable to rust.

You can restore your undercarriage's rust protection with a rust inhibitor spray. These are inexpensive and you can apply them easily. Have your car washed and then wait until it's completely dry, then spray the rust inhibitor on any bare metal in your undercarriage. Make sure that you cover everything, including the wheel wells the bottoms of your door panels if there's exposed metal there. It's a good idea to do this before every winter to make sure your car is fully protected against rust.

Road salt can wreak havoc on a car's exterior, but thankfully auto manufacturers have managed to limit the destruction it can cause with advances in the way that they apply paint to cars. All you need to do is to make sure that you have your car washed regularly, stay away from roadside sludge and apply rust inhibitor spray to your car's undercarriage. With your car fully protected, you won't have to worry about rust eating away at its exposed metal components.