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How to Remove Rail Dust with CarPro IronX and a Clay Bar


Chances are if you have ever owned a light colored vehicle, you have seen tiny red or rust colored spots on the finish. These spots are not your normal dirt and debris and do not come off with just a quick maintenance wash. They actually go beyond the top layer of your finish and some can be buried deep into the clear coat. A lot of people have no idea what these spots are, what causes them, or how to remove them. These spots are referred to as “rail dust”. They can be very frustrating and I’d like to share some helpful tips, otherwise the process can take hours to remove. Here is an example on this silver Range Rover:

rail dust on silver Range Rover


What is Rail Rust:

Rail dust is a term used to describe tiny metal particles that have embedded themselves into your clearcoat. The term was originally used to describe dust that comes off of railroad rails. When vehicles are transported via train there is a lot of friction between the rails and the train wheels. Both parts are outside at all times so they have a built up level of rust on them. This rust flies into the air in dust particles when the train is moving. Eventually these particles settle on the vehicles being transported. They embed themselves into the clearcoat and still continue to rust causing tiny red or rust colored spots in the clearcoat. Vehicles that are transported uncovered are usually worse because of the finish being heated by the sun.

Rail dust does not just come from transportation though. It can come from almost anywhere; rust particle on the road from other cars,  from nearby train tracks,  from your disk brakes, or even from industrial areas. These particles can be very hard to remove but if you take a few special steps the removal process can be a lot easier and less time consuming.


How to remove Rail Dust:

First you will want to do a full wash using The Grit Guard 2×4 Wash Method. It is best to do this in a shaded area to help prevent swirl marks and because you will need to have the vehicle wet during a few of these steps.

Next you will want to use a product called CarPro Iron X Iron Removal on the vehicle. Iron X interacts with the contaminants embedded in your clearcoat and dissolves or loosens them. This is a very easy product to use and it gets the job done. All you have to do is mist it onto the vehicle, wait about 5 minutes for it settle, and then rinse it off. The product goes on clear but will turn to a dark purple color once it starts to interact with any contaminants in the clearcoat, including rail dust. This step will help loosen the particles and make them easier to clay out of the clearcoat.

TIP: Do not let the Iron X dry on the surface. If you’re worried about it drying on the surface do smaller sections of the car at a time.

Iron X is safe on all exterior surfaces and here is what it looks like on this Aston Martin wheel:

iron x removing iron deposits from ashton martin wheels

After the particles have been loosened move onto claying your vehicle. A good clay bar that is great on most paints is the DI Gentle Fine Grade Clay Bar. Some paint finishes are softer or harder than others so there is an Ultra Fine grade and Medium grade available also. When you are claying you will need to spray a lubricant onto the vehicles surface to reduce friction between the clay bar and the clearcoat. This will prevent any marring from occurring. I use Dodo Juice Born Slippery. It comes concentrated and makes about 2.5L of clay lube.

Start by spraying on the lubricant and then GENTLY rubbing the clay bar back and forth against the clearcoat. Clay one panel at a time so your lubricant doesn’t dry. You will feel the clay bar grab at first but once you make a couple passes it will glide smoothly. This is how you know the contaminants are being removed. If an area is still grabbing after a couple passes, make a couple more. It’s a good idea to go back and forth in both directions. Since rail dust is a red or rust color you will be able to see if it is still there or not. Some areas will need a little more elbow grease than others.

using clay bar to remove iron deposits

Once the surface feels nice and smooth then the contaminants (rail dust) should be removed. If they are not gone or being difficult to remove then repeat the previous Iron X step. Most of the time one application will do the trick, but if the rail dust has been there for a long time or is deeper than normal it might take an extra application.

Finish by rinsing off the vehicle and proceeding to the drying process.

Here are some before and after pictures of this process.


rail dust on paint



paint condition after iron deposit removal


iron deposits on the paint


paint condition after iron deposit removal

Once you are done you will have a nice and clean contaminant free surface!

After all that work you are going to want to apply a durable wax, sealant, or coating to help prevent rail dust from occurring again.

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Addison Good of Good Guys Detailing
Addison Good
Good Guys Detailing
South Florida

30 comments on How to Remove Rail Dust with CarPro IronX and a Clay Bar

  1. John L. says:

    Nice work although I am a little surprised that you did not dismount the licence plate. On every detail that I do I “pull the plates”. It gives a more complete effort on the detail. Just a tip. John L. Best Investment Auto Details. Columbus Ohio.

  2. Sultan says:

    Very helpful tips thanks for posting!

  3. Jon says:

    Nice write-up! I have heard many good things about Iron-X and this further supports their top-shelf ranking in terms of rail dust removal. Not to muddy the waters, but the manufacturer also makes a product called Trix, which I believe is a blend of Iron X and Tar X (the latter geared towards removing tar, adhesives, etc.).


  4. Jon says:

    Also….if you think your wheels are rail dust free, spray some of this in the lug nut area and watch the chemical reaction. It’s a great product, indeed. That said, I have jet black body paint and doubt I would ‘see’ the positive effects like I do on my wheels (you guessed it, I haven’t tried yet).

    • Addison Good says:

      Great point! The good thing about this product is that it turns purple when it reacts with contaminants so you can still see it work on black paint. If it is kind of hard to see take a inspection light and look at the paint with it after you apply it.

    • Rui Miranda says:

      CarPro IronX is one of my go-to products. But it is not designed for wheel maintenance: you have to be especially careful with the calipers and the wheel weights.

      • Addison Good says:


        I have used it a few times on wheels when I was out of Sonax Wheel Cleaner. I havn’t noticed any problems but I will keep an eye out for that. Thanks for letting me know!


  5. Buddy says:

    Thank you for the excellent write-up Addison.
    I live in Naples, FL and it would be great to meet you and check out your shop.


  6. Adam B says:

    Very good tip Addison! I used to have a white car and remember these spots were so stubborn, three years ago I had no clue so I just kept coating wax over the top thinking I was doing something to get rid of the spots…. I can say I’ve come a long way in terms of detail knowledge, next time I face a white or light colored car I will know how to attack this issue.

    btw congrats on your business! I remember reading those first couple posts where Todd had you helping detail the mercedes, it seems you have come a long way! about two years ago I started to become much more involved in detailing, maybe someday I’ll expand like you have done, until then I’ll keep learning because I have a lot to learn! Thanks again,


    • Addison Good says:


      Iron X will take care of them every time.

      Thank you, Todd has been a great mentor and a friend. He has helped me come a long way since I first met him.


  7. Mike Cardenas says:

    We use Iron-X in our detail studio and it’s a must-have for any detailer. We have a couple of steel foundries here locally and we’ve started carrying it in our retail store for that same reason, people were just having a difficult time removing rail dust with clay alone. Local automotive stores had nothing for this and some people have resorted to using harsh cleaners in desperation. Great article Addison!

  8. Addison Good says:


    Thanks, the cars around there must be a pain to deal with. Though I’m sure they come out of your shop looking better than new.


  9. Eric S says:

    Great information! I just ordered this product and am looking forward to trying it out. Here in Utah there is so much iron dust in the air that my silver Armada was looking distinctly orange from 3 years worth of rusting rail dust stuck to it! It took me 18 hours to clay it off last time and I’m hoping that Iron-X will shorten that a ton this weekend.

  10. Tom Heise says:

    I have powder coated wheels,how will this iron-x react to them.


  11. Chuck Thompson says:

    I have a 2004 White Buick Custom with the brown spots. I have clayed it once and thought I got all of it, but evidently not. I used a Mequiliars clay bar and it did get a lot of it off, but some spots have returned. I do not live near any railroads as such or any industrial plants. I had a white Chrysler Lebaron and it never had these spots. My question is, where do I get this IronX treatment to use on what has come back. I live in Columbus, Ohio and we have lots of auto stores, etc., lots of body shops do not want to tell you anything. Appreciate any info you can give….Thanks, Chuck

  12. ew says:

    Bought a new prius pearl white and a day after, saw the rail dust. I talked to the dealer and they clay bar the car. Surface is smoother but I can still see orange specks on the hood and roof. Dealer recommend to immediately apply Maxxguard protection. I thought I should wait and see if these rail dust reappears. If I use iron X to remove the remaining rail dust, would those rust spots not come back?

  13. Tony Kiger says:


    If clayed properly the particle should be completely removed and will not be able to come back, however if you have heavy dusting from your brakes or have industrial plants around you may accumulate more over a time and therefore need to repeat this process. When you clay you are pulling the particle out of the clear coat and removing it from the surface.

  14. Diana Anderson says:

    I just bought a 2014 Scion TC which was made and shipped from Japan. While getting my windows tinted, the tint person washed the car and said there was rail dust on the car due to being transported here by train. I do not want to ruin a brand new expensive auto. My husband suggested vinegar. Any suggestons. Buffing causes swirl marks.

  15. Taylor says:

    Thanks for posting this! Because of this post, I was able to get my entire car cleaned up from a bad case of rust on white paint. I had a mishap with a car shop that “forgot” to include the actual brake pad when they reassembled my brakes. Without the brake pad, the metal was grinding really hard before I could get it fixed and then it snowed 6 inches in Colorado! Basically, the entire right and back side of my car was covered in rust!!!

    I wasn’t able to find Iron-X at my local car shops, but they recommended a similar product that I used along with the clay like you recommended. The rust came right up!!! I only spent $30 at AutoZone vs. however much it would cost to get detailed… let’s just say I’m a happy girl!

    • Neciaism says:

      Hi Taylor, What is the similar product if I can’t find the Iron X? I’m a girl with a rust cover white truck that’d like to be happy as well? Neciaism

  16. joey says:

    I have a question I have a white car, I work out at the foundry, American castings. And these little rust particles like this is on my car. Except it’s like 10 times worse. Would this product still be as effective if I use it

  17. Rick says:

    Has anyone ever heard of contaminants in a brand new chrome bumper? I just got a new 2015 Silverado and the back bumper has all kinds of snags when I run a MF towel over it. I understand how the metal can imbed in a paint or top coat, but a metal bumper? Can that happen? I’m going to try some IronX on it and then some clay and see what happens. I’ll update afterwards.

  18. Pam Terry says:

    I have purchased a new white car and have come up with these rust spots. Reading all these posts I thought it was from the trees but now I think I know where it is coming from I live by a railroad tracks. Once I get rid of the spots how do I prevent them from coming back? Will I always have this problem and if all cars get this or just you can see it on the white cars? I am exhausted trying to keep it clean. Help. The strange part is my son lived in the same building and he has a white car and it never had these spots. It it because of a bad paint job it clear coat? Help!

  19. Roy from oz says:

    I recently purchased a vw type 3 1973 model…with a good paint job,..but with rail dust covering the roof and bonnet ETC,….tried iron X based in recommendations above ….works great and removed all dust spots …AMAZING product ….!!!!!

  20. L Morgan says:

    I’m taking delivery of a Dodge Charger SRT 392 in a Granite Metallic color. It is pretty dark so wonder if an IronX app is necessary? I intend to clay in any case. In the long run, on a dark car, will rail dust after washing, claying, pre-wash polish and final protection, really make any difference? Just trying to convince myself the IronX step is necessary. Thanks,

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