Some years ago, I had a very similar problem. But it was police cruisers and suvs. Same material and colors. Some vehicles were lettered years ago and some more recently. I studied our records and put a lotta time into figuring it out. It was the police department where I lived, so I was extra interesed. I realized..... they brought vehicles to me to have me look at them, so I stopped at their parking areas and would look and look and look at the cars. They had assigned spaces. Then, I noticed it was only one side of the vehicles and only to like the first 8 or 10 vehicles at the far end. This end happened to be somewhat close to where they stored their snowplows and other winter equipment. Guess what filled the whole inside of this building..... SALT for spreading on snow covered back roads. This salty air was falling on the cruisers, cause they left all the overhead doors open all the time. Their own salt was doing it. I replced about 5 or 6 vehicles at no charge and after telling them what's happening, I got blank stares, but no offer for reimbursement which was their fault.
