At work I use an underground parking lot. Last week I came back to my car after my day, and I saw hard water dripping down from the concrete, that left like 5 big calcium spot on my car...

Now I'm looking for a way to remove them without a complete paint job! I heard that vinegar would do the job, but since I never tried it, I don't want to mess anything!

Vinegar should dissolve calcium spots without harming the paint. Test first of a non-conspicuous area,like the rocker panel. CLR should also do the trick.

Just use a light colour restorer like T-Cut or similar!!

Ok, I'm late for the answer, but the recipe I use and that works well is:

1 cup vinegar
4 cup HOT water

That's it! Works like a charm.

Just rince and dry as well as possible after to avoid any vinegar smell.

Best Regards,

vinegar works perfectly.
just make sure you eat before doing it,otherwisw you'll get a hell of an appetite!