Blotches on a car body: what are they, where do they come from and how to get rid of them

Have you ever noticed small black dots on the body of your car that cannot be washed off with a regular car wash? Or subtle roughness, similar to inclusions of sand? This is it inclusions is one of the most common, but often ignored, paintwork problems. They not only spoil the appearance of the car, but can also become a source of corrosion if they are not eliminated in time.

Blemishes are microscopic foreign particles that firmly adhere to the surface of the paint or varnish. Unlike ordinary dirt, they cannot be washed off with water or removed with a touchless car wash. Most often they appear after driving on dirt roads, winter use or unqualified polishing. But how to distinguish them from scratches or chips? And most importantly, is it possible to get rid of them yourself without damaging the paintwork?

In this article we will look at what inclusions on a car body are, why they form, what types there are and how to remove them correctly. You will also learn what mistakes car owners most often make when dealing with this problem - and how to avoid them.

What are inclusions on a car body: definition and types

Interspersed (or embedded contaminants) are small particles that are embedded in the top layer of varnish or paint of a car. They can be of organic or inorganic origin, but they all have one thing in common: they cannot be removed with standard detergents. The inclusions not only spoil the aesthetics, but also over time destroy the protective layer of the paintwork, allowing moisture and salts access to the body metal.

Based on their composition and origin, inclusions are divided into several types:

• 🔴 Iron-containing (iron scale) - the most dangerous, as they oxidize and cause rust. They appear from brake dust, railroad crossings or metal shavings from the road surface.
• 🟤 Clay or sand - particles of clay, sand or road dust, which at high speed are “imprinted” into the varnish. Often found after driving on dirt roads.
• ⚫ Carbon (soot, resins) — exhaust gas residues, bitumen stains or industrial emissions. Particularly noticeable on light-colored cars.
• 🟡 Coloring (from insects, bird droppings, tree resin) - organic inclusions that over time “stick” to the surface and penetrate into the micropores of the varnish.
• 🔵 Salt — crystals of reagents that are used in winter. After drying, they become abrasive and scratch the varnish when washed.

The most insidious - iron-containing inclusions. They not only spoil the appearance, but also start the process of corrosion under the varnish. They can be recognized by reddish dots that grow over time. If such particles are not removed in time, they will turn into pockets of rust, and then local painting will be required.

⚠️ Attention: Do not confuse inclusions with micro scratches or holograms after polishing! The inclusions feel like roughness when you run your finger, and the scratches feel like grooves. Holograms are visible only under direct light and cannot be felt to the touch.

Where do inclusions come from: 7 main reasons

Inclusions do not appear on their own; their source is always external influence. Here are the most common reasons:

1. Aggressive driving on dirt roads. Sand and small stones under the wheels of other cars rise into the air and “sandblast” your body. The bumper, hood and lower parts of the doors are especially vulnerable.
2. Winter operation. The reagents that are scattered on the roads contain metal salts. They stick to the body, and after drying they become an abrasive.
3. Poor quality washing. If a car wash uses dirty brushes or does not dry the car correctly (for example, with a cloth containing sand), dirt particles are rubbed into the varnish.
4. Industrial emissions and resins. Near factories, sawmills or after driving under poplar trees (sticky buds), sticky particles settle on the body, which then harden.
5. Brake dust. This is especially true for cars with disc brakes. Metal dust from the pads settles on the wheel arches and lower parts of the body, and is then carried by the wind.
6. Incorrect polishing. If you use abrasive pastes without preliminary cleaning, dirt particles become clogged into the pores of the varnish.
7. Bird droppings and insects. Their residues contain acids that corrode the varnish and leave behind microscopic craters where dirt later gets clogged.

I wonder what inclusions appear more often on dark cars - not because they are more susceptible to contamination, but because they are simply easier to see on a black or blue body. On light-colored cars, the problem becomes noticeable only upon close inspection or after applying protective coatings (for example, ceramics), which highlight all defects.

How to detect inclusions: 3 reliable ways

Before dealing with inclusions, you need to make sure that these are exactly them and not scratches or holograms. Here's how to identify them:

1. Visual inspection from different angles

Look at the body in direct sunlight or with a bright LED lamp. The inclusions will look like:

• 🔍 Small black or red dots (iron, soot).
• 🟤 Rough areas similar to sandpaper (sand, clay).
• 💎 Shiny inclusions (metal shavings).

If defects are visible only from a certain angle and disappear when the lighting changes, these are holograms, not inclusions.

2. Tactile test

Gently run your finger over the suspicious area. The inclusions will feel like:

• 🧂 Small grains of sand (if it is sand or clay).
• 🧲 Rough film (soot, resins).
• 🩹 Sticky spots (remains of insects or bird droppings).

Scratches, on the other hand, feel like grooves rather than bumps.

3. Test with polyethylene

Wrap your finger in cling film and run over the surface again. If you feel resistance, this is 100% inclusion. This method helps to distinguish them from microscratches, which cannot be felt through the film.

⚠️ Attention: Do not use your fingernails or metal objects to check! You may scratch the polish and make the problem worse.

How to distinguish inclusions from rust?

Rust usually appears on chips or scratches and has a reddish tint that “grows” over time. The inclusions are static and do not increase in size. If the red dots are not removed by clay, but do not spread, these are iron-containing inclusions, not corrosion.

Is it possible to remove inclusions yourself: pros and cons

Yes, you can get rid of inclusions with your own hands, but there are nuances here. Before starting work, assess the risks:

Removal method	Pros	Cons	Cost
Automotive chemicals (particle cleaners)	Quickly, without the risk of damaging the paintwork	Does not remove deep inclusions	500–2000 ₽
Clay for detailing	Removes 90% of stains, safe for varnish	Requires skill, can scratch the body	300–1500 ₽
Polishing	Removes even deep spots	Removes a layer of varnish, requires protection after	1000–5000 ₽
Professional processing	Guaranteed result, safety of paintwork	Expensive, takes time	3000–10 000 ₽

If the inclusions are fresh (appeared less than a month ago) and have not yet ingrained themselves deeply into the varnish, it will deal with them auto chemical goods or clay. For old contaminants (especially those containing iron), it may be necessary to chemical removal special compounds or even light polishing.

The safest way for a beginner is clay for detailing (for example, 3M Clay Bar or Sonax Profiline). It works like a magnet for contaminants, pulling them out of the pores of the varnish. But it is important to follow the technology, otherwise things could get worse.

Step-by-step instructions: how to remove inclusions from the body

If you decide to deal with inclusions yourself, follow this algorithm. It is suitable for most types of pollution, except for deep iron-containing ones (they require a separate approach).

Step 1: Washing and Preparation

Start with contactless car wash under high pressure to remove surface dirt. Then:

1. Apply car shampoo (for example, Karcher RM 801) and wash the car with a soft sponge.
2. Rinse off the foam thoroughly so that there are no streaks left.
3. Dry the body microfiber towel or compressed air.

Step 2: Claying

Take velvet clay (for example, Nanolex Clay Medium) and divide it into small pieces. Next:

1. Wet the surface quick detailer spray (or diluted shampoo).
2. Gently move the clay over the body no pressure, periodically folding it so that dirt does not scratch the varnish.
3. After treatment, wipe the surface with clean microfiber.

If the clay quickly gets dirty, this is a sign of strong inclusions. In this case, re-processing or a more aggressive clay (for example, heavy-duty).

Step 3: Removing Iron Contaminants

For red spots (scale), use special removers (for example, CarPro Iron X or Sonax Full Effect). They react with iron, dissolving it. Algorithm:

1. Apply the product to a dry surface.
2. Wait 3-5 minutes (until the liquid turns purple).
3. Rinse off with plenty of water.

If after this procedure there are dark spots left, they will have to be polished.

Step 4: Paint Protection

Once the inclusions are removed, the varnish becomes vulnerable. Be sure to apply:

• 🛡️ Wax (for example, Collinite 845) - for short-term protection.
• 💎 Ceramic coating (for example, Gyeon Ceramic Coating) - for long-term protection (2–5 years).
• 🧴 Sealant (for example, Poorboys Sealant) is an average option in terms of price and efficiency.

⚠️ Attention: If after processing with clay there are still roughnesses, do not rush to polish! Try repeating the procedure with softer clay or use resin remover (for example, Turtle Wax Bug and Tar Remover).

What not to do when removing inclusions

Many car owners, in an attempt to save money or speed up the process, make mistakes that only damage the paintwork. That's what strictly prohibited:

• 🧽 Use household chemicals (for example, Domestos or Mole). It corrodes the varnish and leaves matte stains.
• 🧼 Wipe the body with a dry cloth. This scratches the varnish and rubs the dirt even deeper.
• 🔧 Polish without experience. Improper polishing will remove too much varnish and the body will become dull.
• ☀️ Work in direct sunlight. Stains removers dry quickly and may leave streaks.
• 🧴 Use abrasive pastes (for example, GOI) without pre-cleaning. They will only deepen the defects.

Also, do not skimp on materials. Cheap clay or fake iron removers may not only not help, but also ruin the varnish. For example, poor quality Iron X Instead of a purple color, it gives a dirty brown tint - this means that the reaction with iron does not occur, and the product is useless.

When to turn to professionals

Not all inclusions can be removed in a garage environment. Contact detailing center, if:

• 🔧 The inclusions have penetrated deeply into the varnish (they feel like hangnails).
• 🎨 After removal, matte spots remained (which means the varnish is damaged).
• 🔴 The red spots did not disappear after Iron X (this is the beginning of corrosion).
• 🚗 The car is light, and after processing holograms appeared.
• 💸 You are planning to sell your car and want the perfect paintwork.

Professionals use multi-stage polishing, ultrasonic cleaning and nanocoatings, which cannot be repeated at home. The average cost of complex processing is from 5,000 to 15,000 rubles, but this is cheaper than repainting the part.

If you doubt whether you can do it yourself, do a test on a small area (for example, on a bumper). If you are satisfied with the result, continue. If not, it’s better to entrust the car to specialists.

FAQ: Frequently asked questions about inclusions on the body

Is it possible to prevent the appearance of inclusions?

Yes, but they cannot be completely avoided. To minimize risk:

• 🛡️ Apply ceramic coating or wax — they create a protective layer.
• 🚿 Wash your car at least once every 2 weeks using touchless foam wash.
• 🌳 Avoid parking under trees (tar, bird droppings).
• 🛣️ After driving on primers, wash the body immediately.

Also helps anti-gravel film in vulnerable areas (hood, bumper).

Why are iron-containing inclusions dangerous?

They start the process under-film corrosion. Iron oxidizes, rust spreads under the varnish, and after 1–2 years, through damage will appear in this place. It is especially dangerous for cars without a galvanized body (for example, old foreign cars or budget models).

If the red spots do not disappear after Iron X, they must be removed mechanically (by polishing) or by local painting.

Can WD-40 stains be removed?

No! WD-40 dissolves some types of resins, but does not cope with iron, sand or salts. In addition, it leaves a greasy film that interferes with further processing. To remove inclusions, use only specialized products.

How much does professional stain removal cost?

The price depends on the degree of pollution and the size of the car:

• 🚗 Easy cleaning (clay + iron remover) - 2 000–4 000 ₽.
• 🔧 Full detailing (cleaning + polishing + protection) - 8 000–15 000 ₽.
• 🎨 Local painting (if the inclusions caused corrosion) - from 5,000 ₽ per part.

In the regions, prices can be 20–30% lower than in Moscow.

Does polishing help remove inclusions?

Yes, but only if they are shallow. Polishing removes the top layer of varnish along with dirt. However:

• ✅ Suitable for old inclusions that were not removed by clay.
• ❌ It won't help if the varnish is already damaged by corrosion.
• ⚠️ After polishing, be sure to apply a protective coating!

For polishing use soft pastes (for example, 3M Perfect-It) and polishing machine with speed control.