What is a Clay Bar Treatment? (Full Explanation)

If you are interested in having your vehicle professionally detailed, or are a DIY detailing enthusiast, then you have probably heard of clay bars and wondered what they actually are, how to use them, and why they’re important. In this guide, I’ll answer all the questions that you might have about claying a car.

What is a Clay Bar?

Clay bars are made from synthetic resins and polymers which feel slightly sticky and can be remoulded and shaped. Clay bars are designed to remove embedded contamination from a car’s clear coat layer of paint which cause it to feel rough. Using a clay bar leaves the paintwork feeling ultra-smooth and clean, ready for polishing or protection. Clay bars can be used on painted surfaces and glass.

Over time, the exterior surfaces (paint, wheels, glass) on a car become “contaminated” causing it to feel rough even when freshly washed. These “contaminants” cannot be removed with routine washing as they are embedded in the clear coat. These contaminants include:

  • Iron particles (from brake discs, industrial fallout and rail dust)
  • Tree sap
  • Tar
  • Mineral deposits
  • Dried bugs
  • Overspray

Using a clay bar will “shave down” or pull out these contaminants from the clear coat and hence leaving it feeling nice and smooth.

Why is Clay Bar Treatment Important?

Removing environmental contaminants from the exterior of the vehicle via the claying process is important for three reasons:

  • The contaminants can damage the clear coat if left for a long period of time so must be removed
  • Claying leaves the paintwork looking cleaner
  • Claying prepares the paintwork for machine polishing and protection

Do Clay Bars Have Any Disadvantages?

Clay bar treatment is essential before polishing the paintwork and keeps the vehicle free from nasty contaminants which cause it to look dull and feel rough. However, clay bars are abrasive which means that they are highly likely to cause some level of marring or swirl marks in the clear coat layer of paintwork.

There are several things you can do to minimise the marring (which I will discuss in the next section), however especially on soft paintwork it’s very likely that the clay bar will leave some fine scratches behind. Fortunately, these scratches are quite easy to remove in the polishing stage, but if you don’t plan on polishing the car then you should consider using a glaze to mask these defects.

If you are looking for more information on the effect of clay bars on the paintwork, please read this article.

How Do You Use a Clay Bar?

Clay bars are really quite simple to use, but there are several things that you need to do before you even think about claying.

Here’s how to prepare the vehicle for a clay bar treatment:

  • Pre-wash the vehicle using a citrus pre-wash or snow foam to loosen the dirt and then rinse it away using a pressure washer
  • Use a microfiber wash mitt and dedicated car shampoo (ideally one which is free from wax/ gloss-enhancers) to clean the paintwork, then rinse again
  • Use a tar remover spray to gently remove tar spots typically found on the lower sections of the car
  • Use an iron fallout remover spray over the entire vehicle to remove embedded iron particles

Although clay bars are capable or removing tar and iron contamination, I strongly advise that you use these dedicated chemicals to try and remove as much of these contaminants as possible prior to claying. The more “contaminant-free” the paintwork is, the less likely you are to cause marring/ swirls during the claying process. It will also speed up the decontamination process and make it more effective. Please read this article for more information.

Once these steps have been completed, the car is ready to be clayed.

To clay bar a car you will need:

  • A good-quality automotive clay bar or clay mitt
  • A clay bar lubricant

I personally use clay bars from several brands including The Rag Company, Bilt Hamber and Garage Therapy. I’ve found all these to be good options. Do not be tempted to go for cheap alternatives as they are much more likely to cause damage or be ineffective.

The clay bar lubricant does exactly what it says on the tin and helps the clay bar glide across the paintwork to reduce the risk of marring. There are several options to use from including:

  • Car shampoo and water in the wash bucket or in a spray bottle
  • Dedicated clay bar lubricants e.g. Stjarnagloss Glir
  • Waterless/ rinseless wash products e.g. Optimum No-Rinse

Avoid using things like dish soap (or any other household products) as these do not provide enough lubrication and can cause staining/ damage. Also try not to use any quick detailer sprays or shampoos with waxes/ gloss-enhancers built-in to the formula as you don’t want to be laying down any protection during this stage of the detail. Here is a guide to the best clay bar lubricants for more information. Once you have everything together, you’re ready to clay the vehicle.

Here’s how to use a clay bar:

  • Cut the clay bar into thirds so you have a manageable chunk
  • Run the piece of clay bar under warm water to soften it and then knead it into a flat disk
  • Spray the clay bar lubricant (or use a wash mitt if the lubricant is in a bucket) onto both the paintwork and the clay bar liberally
  • Use straight-line motions to gently glide the clay bar over the paintwork using no pressure
  • Once you feel the contaminants have been lifted, move onto the next section
  • Keep checking the clay bar for visible contamination and then fold it to reveal a fresh surface
  • Rinse the panel and dry as normal using a microfiber towel

In order to make this process as effective as possible, and reduce the risk of causing marring as much as possible, there are several things that you need to keep in mind during the claying process:

  • Check the clay frequently and fold it so the contaminants are not rubbed into the paintwork which otherwise will damage.
  • If the clay becomes too contaminated, use a fresh piece.
  • Never drop the clay bar on the floor. If you do, you will need to use a new piece of clay. Do not be tempted to just fold it and carry on!
  • Use straight-line motions and be gentle. You do not need to apply any pressure.
  • Do not keep claying the same area. You should only need to go over an area once.

What Should You Do After Clay Barring?

After using a clay bar you have two options:

  1. Protect the paintwork
  2. Polish and then protect the paintwork

The best course of action really depends on what you want to do next, and how much marring has been left behind by the clay bar.

On some cars with very hard paint (e.g. most Audi and BMW cars), there is a possibility that the marring will be so minimal that it may not bother you at all. In this case, you can go right ahead and protect the paintwork with a wax or sealant.

However, on cars with soft paint (e.g. Mazda or Honda) then you will likely need to polish the paintwork to remove the marring. Also, if you plan on protecting the car with a ceramic coating then you should also always polish the paintwork after claying and before applying the coating.

Car polishing, also known as paint correction and enhancement, is the process of removing a very fine layer of clear coat paint. The aim is to remove defects such as marring, scratches and swirl marks in order to enhance the gloss and prepare the surface for protective coatings. Polishing and waxing are NOT the same thing. Please read this article for more information on polishing.

How Often Should You Use a Clay Bar?

I’m a strong advocate that clay barring should not be done as part of a routine, and only when necessary. This is to avoid inflicting excessive marring which needs to be polished out frequently. As a result, there’s no exact frequency which you should be claying a car. Instead, you should only clay when the paintwork feels rough after it has been washed, indicating that the clay bar treatment is needed.

Contaminants are more likely to stick to the paintwork if it is not washed as frequently, this is why I’d advise that a vehicle is washed at least every 2 weeks to keep it in the best condition possible and reduce the need for frequent clay bar treatment. Storing the vehicle away from the side of the road, and ideally undercover will also help to prevent the build-up of these contaminants. With proper care, a car should not need claying more than once every 1-2 years.

Frequently Asked Questions?

What is the difference between a clay bar and clay mitt?

Clay bars and mitts have the same function but there are several differences between them including:

  • Clay bars are typically more aggressive so will remove heavier contamination more easily, but are likely to cause more marring than a clay mitt
  • Clay bars have a smaller surface area so it takes longer to treat the vehicle compared to when using a clay mitt
  • Clay bars are easier to bend around tight areas compared to clay mitts
  • Clay bars cannot be reused whereas clay mitts can if they are kept clean and well maintained

Please read this comparison between clay bars and clay mitts for more detail.

Can you use a clay bar on a ceramic coating?

You shouldn’t use a clay bar, mitt, or cloth on a ceramic coated car because it will break down the coating, or cause swirl marks. You can use an iron fallout and tar remover instead to safely remove contamination without using clay. Please read this article for more information.

Do clay bars remove scratches?

Clay bars do not remove scratches. In fact, due to the abrasive nature of a clay bar it is likely to cause some minor clear coat scratches and marring itself which will need to be removed by polishing the paintwork to achieve a defect-free finish.

Do clay bars remove old waxes?

Clay bars are abrasive so in most cases, will remove waxes and sealants. Sometimes, clay will not remove more durable waxes/sealants and are unlikely to remove ceramic coatings which require machine polishing to be properly removed.

Do you need to polish after using a clay bar?

It is usually necessary to polish a car after using a clay bar because the clay will cause some marring which needs to be corrected by polishing the paint. However, If the marring does not bother you, then you can skip this step. Please read this article for more detail.

Do you need to wax after using a clay bar?

A wax or sealant should always be applied to the car after using a clay bar. The clay bar will remove any old protection so a wax or sealant needs to be applied to ensure the paintwork is protected. If you are also polishing the car, then you should do this immediately after claying and before applying a wax. Please read this article for more information.

Should a car be washed before using a clay bar?

The vehicle should always be thoroughly washed before using a clay bar. It is also recommended to perform a “chemical decontamination” using iron fallout remover and tar remover before claying the car.

Can you use a clay bar on glass?

Clay bars can be used on glass, including the windshield. Make sure to wash the glass using car shampoo first and then use plenty of lubrication in the form of a clay lubricant spray, or car shampoo to glide the clay bar across the glass in straight line motions, then rinse the surface and dry.


To book your car in for a valeting or detailing service get in touch today by either calling, emailing or completing the contact form and Heather will be in touch shortly

07894 074109
8:30-6:00 Mon-Sat


Heather is a professional car detailer & valeter based in Cheshire and the owner of Auto Care HQ. A familiar face in the car detailing community, she has written over 200 car detailing guides on autocarehq.com and has produced over 165 videos on the Auto Care HQ YouTube channel.

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