Many cities in snowy parts of the country are switching from sodium chloride (rock salt) to brine, a solution that contains magnesium chloride. The brine solution is cheaper, easier to apply and is gentler to paved surfaces. In these cities – where the freeze-thaw cycle creates potholes by shrinking and expanding the pavement – sodium chloride exacerbates the road damage by further eroding the holes in the road. Magnesium chloride doesn't really affect the fissures in the road's surface and there is less waste when it's applied, making it more economical.

While this is great news for the roads, it's bad news for drivers. Magnesium chloride may be gentler on pavement, but it's rougher on cars. Not only is it more corrosive than salt, but the mist from the sprayed liquid clings better to car parts, especially the undercarriage, and seeps into crevices and crannies. This means that body panels, brake lines, gas tanks and anything underneath the car will be more likely to rust, and quickly. If your city has switched to magnesium chloride for snow removal, here are some things you'll need to do to protect your car's paint and components.

1. Wash your car more often.

If you normally wash your car every few weeks in the winter to remove the crystallized salt, that may be too long to wait between washes. Magnesium chloride is faster acting and can work its way into smaller areas than salt can. When the city snow removal trucks are out in full force, you'll need to wash your car twice as often to prevent corrosion.

2. Use soap with a low pH.

When salt and magnesium chloride dissolve in water, they produce an acid. However, magnesium chloride produces a stronger acid, so it's more corrosive. Neutral or high pH car wash soap won't neutralize the high pH acid – you need a low pH soap to neutralize and break down the acid and counteract its effects. If your car wash offers a choice of soaps, choose the one with a lower pH.

3. Wax your car regularly.

Wax can help create a protective barrier that can make it harder for magnesium chloride to penetrate the car's paint. Wax your car before winter, and opt for the spray wax each time you go through the car wash.

4. Keep your car cold.

The corrosive acid is formed when magnesium chloride dissolves. Warmer temperatures often mean higher humidity, even in winter, and higher humidity makes magnesium chloride dissolve. Therefore, colder temperatures can slow down the damage. Parking in a covered or heated garage can actually speed up the corrosion process, but keeping the vehicle outside in the cold can slow it down.

5. Don't follow the snow removal truck.

Getting behind the salt truck is great for drivers because they benefit from the traction provided by unmelted salt crystals. However, since magnesium chloride is applied as a liquid, drivers immediately behind the brine truck will be hit by the full-strength mist. Let the trucks get a head start so you get less of the damaging mist.

6. Fix the scratches.

Scratches are breaks in the paint's surface that can expose bare metal, leaving it vulnerable to rust. Magnesium chloride will attack raw metal and begin eating away at it quickly, so get the scratches and dings repainted before winter.

7. Get your car rustproofed.

Rustproofing your car is one of the most effective things you can do to protect against the damaging effects of magnesium chloride. It provides a protective barrier and seals minute breaks in the surface. Once a car starts to rust, you have to remove the rust by grinding and repainting the metal – a time-consuming and expensive job. It's cheaper and easier to re-apply rustproofing every few years than to tackle rust that's already begun.

Magnesium chloride may be a boon to cities that need to melt snow, but it can be very rough on vehicles. If your city uses it, you'll need to be aggressive in getting it off your car. Keep the paint free from scratches, wash and wax your car frequently, and talk to a rustproofing specialist about treatments that can protect your car from this damaging chemical.

For more information, contact ValuGard or a similar company.