DETAILING MY CAR > Removing Cement and Mineral Spots

Removing Cement and Mineral Spots

Cement and hard minerals can leave some serious damage on a cars finish

There is an annoying problem that can happen to cars parked in underground parking lots. The problem happens when the ceiling above your car is leaking water. This is pretty common where I live – it’s so wet here all the time. What happens is the water leaches through the cement, carrying a lot of minerals with it. When this mess dries on your car’s paint it leaves white spots that won’t wash off.

In this post I am going to explain how to remove these mineral spots and how to restore your car’s finish. This is a challenging problem. In my auto detail days we worked with a large apartment management company – they operated three huge complexes in our area and all of their garages leaked to some extent. We had a lot of practice with this issue. So, read on for some tips on taking care of this problem at home. You can avoid an expensive trip to a body or detail shop.

Identifying the Cement Problem

You parked in the garage last night only to see something on your car’s paint the next day. You try to rub it off with your finger and nothing happens. Next, you try a wet towel to see if that wipes it off. No luck. You put some thought into it and grab some wax to see if you can get it off that way. No change. How do you get these spots off of your car?

When the client first brought the damaged car into my detail shop, I wrestled with this problem for quite a while. I first used a power buffer and some extremely gritty polishing compound to get the stuff off. It worked, but it took quite a toll on the car’s paint. There had to be a better way.

I did some research on mineral stains and found that they are closely related to hard water spots that can form on a car. When dealing with the water spot problem at the detail shop, I found that vinegar removed the mess.

Professional Steps to Remove Cement Mineral Spots

I had the crew wash and dry our customer’s damaged car and bring it into the shop. We poured some vinegar into a spray bottle and soaked down the mineral spots on the hood and roof of the car. We let it soak into the stuff for about 15 minutes. Next we took some microfiber towels and soaked them with even more vinegar. We rubbed down the spots with the towels, and the mineral stains slowly began to dissolve.

It turns out that the mineral stains are alkaline while vinegar is an acid-based liquid. The vinegar releases the stains. Fortunately, vinegar is very gentle on a car’s paint job. It slightly dulls the finish, but that is nothing that a quick hand wax can’t cure. Plus, who can resist the smell of a fresh salad?

Waxing the Dull Paint and Shining the Car Up

Once we had waxed over where the mineral stains had been, the car looked great. The only problem was that the areas we waxed looked better than the rest of the car! Oops. We had to wax the whole car to make everything look shiny.

The apartment management company was more than happy to pay us to fix the problem. It beat having the renter’s car repainted – and it kept them happy. Heck, they got a great-looking car out of the deal. I know I am a little OCD and any spots on my car would drive me crazy – but mineral spots look so bad that even someone who isn’t a car nut couldn’t live with it.

So, to remove mineral spots from cars you need to break out the vinegar and wipe the stuff off. Your last step is to give the car a wax job to restore the finish and make it shine. Don’t panic if this happens to your car – you can fix this problem yourself. One last word of advice: If the roof over a particular parking stall is wet, move to another one.

2 comments on “Removing Cement and Mineral Spots

  1. This just happened to my car and it’s on the windshield.
    It’s also on the paint but mostly my windshield.
    I tried a little bit of vinegar so is the trick the same on the windshield?? I just wiped it on and wiped it off and it wasn’t coming off. I did not leave it on for 15 minutes maybe I should try this for the windshield what do you think??

    • Hi Tracey. It will work on the glass also. Let it soak into the deposit on the glass for quite a while – like an hour. Keep wetting the area down with the vinegar…it will slowly evaporate. It will come off but it takes some time.

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