Sounds strange enough, right? Well, this happened to me last week after owning my 04 hatch for only 3 days. It had been raining cats and dogs here in Milwaukee for two days and I come out the parking structure after work to find my car covered in what turned out to be calcium deposits. This was a result of the water seeping through the stone and concrete of the parking structure onto the roof of my car. Here's what it looked like (click image to enlarge):

Supplies needed to safely remove the calcium:
1 - bottle of distilled white vinegar
1 - soft sponge
1 - pair of rubber gloves (unless you want to smell like a pickle for a day or two)
The supplies came out to a grand total of $3.85 at the local grocery store.
I started off by shampooing the car using Meguiar's shampoo. This by itself removed a small amount of the calcium but a vast majority was still there. Next I applied the distilled white vinegar to the sponge and began softly scrubbing the car. The calcium disappeared almost instantly and the vinegar worked like magic. It only took a minute or two to clean the entire roof. REMEMBER: The vinegar is an acid and should be washed off immediately! It will also remove any wax that is already on your vehicle. I then thoroughly rinsed my car and shampoo'd it again for good measure. After that I polished and waxed the car as I normally would and she was good as new!
I just thought I would share this odd lesson that I learned the hard way. Hopefully this will spare someone the headache and frustration that I endured.
-Johnny

Supplies needed to safely remove the calcium:
1 - bottle of distilled white vinegar
1 - soft sponge
1 - pair of rubber gloves (unless you want to smell like a pickle for a day or two)
The supplies came out to a grand total of $3.85 at the local grocery store.
I started off by shampooing the car using Meguiar's shampoo. This by itself removed a small amount of the calcium but a vast majority was still there. Next I applied the distilled white vinegar to the sponge and began softly scrubbing the car. The calcium disappeared almost instantly and the vinegar worked like magic. It only took a minute or two to clean the entire roof. REMEMBER: The vinegar is an acid and should be washed off immediately! It will also remove any wax that is already on your vehicle. I then thoroughly rinsed my car and shampoo'd it again for good measure. After that I polished and waxed the car as I normally would and she was good as new!
I just thought I would share this odd lesson that I learned the hard way. Hopefully this will spare someone the headache and frustration that I endured.
-Johnny