CHICAGO (CBS) — By now, most cars are coated in a salty, dirty muck after this week’s snow and extreme cold.

As CBS 2’s Ed Curran reports, it’s important to get that grime washed off before it warms up this weekend.

At Glenview Shell, Peter Louras sees a lot of cars. When he gets them in the air, he really sees the damage from rust, including components like the brake lines.

In this case, it’s on a car that’s only about eight years old. That’s why he says you have to wash the salt off the parts of the car you can’t see.

There’s more to a wash here than meets the eye.

“We want to get the undercarriage washed,” said Ed Adomaitis, manager of Platinum Car Wash in Morton Grove. “We have a rust inhibitor to protect the bottom from salt.”

That typically only costs a few extra bucks at the car wash.

Car owners need to wash the salt off frequently to avoid damage.

The salt gets activated by some water.

So, don’t wait for rain to rinse it away, but wash the car with high pressure and soap from top to bottom.