This car spends it time in a newly constructed parking garage. The owner noted some staining on the hood of the car. Upon inspection, it appeared to be from concrete/lime runoff. This type of lime can very quickly etch unprotected clearcoat and over time can also etch protected clearcoat. When I initially inspected the vehicle I did a small test spot to see if mechanical decontamination could remove the staining. It did successfully do so and we schedule the work for the upcoming weekend. By the time we performed the work, less than a week later, the deposit had already started to etch the finish such that the clay bar was no longer effective at removing the staining. As a result, we shifted to chemical decontamination with a mild acidic mineral deposit remover. This was able to remove the staining. This was followed by an alkaline wash to neutralize the acid. Finally, the area got a free rinse to remove any remaining residues. After that was complete, the hood was polished to remove any trace marring from the process and then blended into the front fenders to give a uniform appearance. The remainder of the vehicle was thoroughly decontaminated and then sealed to protect the paint until further work could be done.