When a car is stolen, often times the thief is looking to resell some of the parts or the whole car all together. But if the thief sees the car's VIN number on multiple windows, they might think again.

It's called VIN-etching. The vehicle's VIN number is engraved onto multiple windows towards the bottom. And because acid is used to apply the VIN number, it's hard to remove making the car useless to someone who's trying to make some money.

"It would cost a lot of money to replace the glass. One of the most expensive items on the vehicle." said Theresa Podguski from AA.

Whether it's for resale value or individual parts, VIN etching on the vehicle could prevent it from being taken in the first place. Podguski from AAA in Allentown is working with the Lehigh County Auto Theft Task Force to acid etch as many cars as possible. Instead of having your VIN in one place, having it on all the windows makes the glass nearly impossible to sell, and makes it hard to dispose of the vehicle after being stolen. Podguski said people come back year after year to get the free service.

She said, "We have people who definitely have been here before, and they've told us that they've had their car etched and come back and look forward to the event."

And some people liked it so much they got all their vehicles etched in one day.

"We've had a steady number of people coming in. Some people have left and went home and actually got another vehicle and came back with that. So we're doing really well today."

According to All-State, a number of insurance agencies will give discounts to drivers who have VIN-etching on their windows.. You can also buy kits so you can do it yourself. Check out the AAA website for future events.