Everything About Car Polishing Compound

Your car's paintwork has microscopic wash scratches, a dull haze that shows up in sunlight and perhaps a resin mark that never came off. Polishing compound sorts that out. But only if you use the right one, the right way. This guide explains what it is, how to choose between the types available and how to apply it without damaging anything along the way.

What polishing compound is and what it does

Polishing compound is an abrasive. Unlike wax or sealant, which sit on top of the paint to protect it, polishing compound works on the clear coat itself. It removes a tiny amount of material to level the surface and erase defects sitting at the surface of the paint: wash scratches, water marks, light oxidation, stains from bonded grime.

This is the difference that confuses most people. Wax hides. Polishing compound corrects. If the paint has a fine web of scratches that only shows in sunlight, wax won't remove it; only polishing compound will, because it works on the clear coat instead of sitting on top of it.

What polishing compound is made of

A polishing compound has three families of ingredients working together. Mineral abrasives in suspension are what actually wear down the clear coat and level the scratches; the coarser they are, the more material they remove and the faster. Oils and lubricants control friction so the product doesn't dry or grab too early, especially by hand. Finishing agents, often waxes or light polymers, leave the surface sealed and glossy once the abrasive has done its job.

The grit of the abrasives is what separates a cutting product from a finishing product. The finer the grit, the less material it removes. But also the fewer marks of its own it leaves behind.

Types of polishing compound by cut

There is no universal polishing compound. There are grades, and using the wrong one is like sanding wood with wall sandpaper: either it removes nothing, or it ruins the piece.

Cutting (No. 1 / heavy)

This is the most aggressive grade, designed for deep scratches, severe oxidation or sanding marks left by a poorly finished bodywork repair. It removes a lot of material, very quickly. For that reason it is also the one most likely to burn through the paint on edges and body lines if applied badly, especially with a rotary machine. It's a job for someone who already knows what they're doing, or is willing to learn carefully. If your paint only has the fine scratches of a careless wash, you don't need this. Go straight to the next grade.

Medium / refining (No. 2)

It corrects what the cutting compound left behind and tackles moderate defects on its own: visible wash scratches, light oxidation, stubborn water spots. It's the balance point between removing material and not leaving marks of its own. It works well by hand and with a dual-action polisher.

Finishing / fine

The finest grit of all. It doesn't correct deep scratches. Its job is to remove the holograms the previous grades leave behind and deliver the final, mirror-like gloss. It's the step that separates a reasonable polish from a showroom finish.

"All-in-one"

Products that combine an abrasive with a sealant or wax in the same application, to save a step. They work well for light maintenance on paint that is already well kept, with minimal defects. What they don't do is replace the cut, refine, finish sequence on genuinely damaged paint. In that case, a single pass will never get you there.

Measuring clear coat thickness before cutting

Before deciding on the grade of compound for a car you don't know well, such as a used one, it's worth measuring the clear coat thickness with a paint thickness gauge. It's a small magnetic device that gives a reading in microns when held against the panel.

The reading on its own doesn't tell you much. What matters is comparing panels. A bonnet or door with a much higher reading than the panels around it has been resprayed, and a resprayed area almost always has less margin, because it has already lost thickness during the previous preparation and painting. On those panels, use Medium compound where elsewhere you would use cutting, and always test on a small area first. On a new car with factory paint, this concern hardly exists.

Which compound to use for each defect

A quick table to decide without guessing.

Defect or scratch	Recommended compound	Recommended pad
Fine, shallow wash scratches (you can't feel them with a fingernail)	Redex Polishing Compound 250 ml, Medium variant	Orange or yellow foam
Holograms or marks left by a previous polish	Redex Polishing Compound 250 ml, Fine variant	Soft white or black foam
Light oxidation, dull paint on areas exposed to the sun	Medium compound, then Fine	Orange foam, then white foam
Spot touch-ups on a small area (door, bonnet)	Redex Polishing Compound 125 ml	Hand foam applicator
A scratch you can feel with a fingernail, but that doesn't reach the primer	Redex Scratch Remover 250 ml (disguises rather than removing material)	Microfibre cloth or hand applicator
Deep scratches down to the primer or bare metal	Polishing compound won't fix it; it needs a bodywork/paint repair	-

It's worth pausing on the Scratch Remover row, because this is where most people get it wrong. It is not an abrasive polishing compound removing layers of clear coat. It's a product that fills and visually disguises the scratch. Good for everyday use. Don't confuse the two mechanisms: one removes material, the other hides the scratch.

Tools: by hand, rotary or dual-action

By hand is the safest place to start. There's no motor speeding up a mistake, you control the pressure in real time, and for fine scratches or spot touch-ups it's perfectly sufficient. It just takes more time and more elbow grease.

A rotary machine removes material quickly and gives the most level finish there is. It is also the least forgiving. It spins on a single axis, concentrates heat in one spot if you linger too long, and is the tool most associated with burning through paint on edges. It's not for your first time.

A dual-action polisher spins and oscillates at the same time, which spreads the heat and makes mistakes much harder to make. It's the best option for anyone starting out at home. Slower than a rotary. Safer than one too.

Pads and cloths: which to use

The pad works together with the compound, not on its own. The same compound gives different results depending on how aggressive the pad is.

• Orange foam. The most aggressive of the foams, for cutting and for Medium compound.
• Yellow foam. In between, good for refining.
• White foam. Soft, for finishing and for Fine compound.
• Black foam. The softest, mostly for applying wax or sealant after polishing.
• Wool. The most abrasive of all, reserved for heavy cutting with a rotary machine and experienced hands.

For hand application, a foam applicator does the same job as a machine pad, on the scale of one hand. It's the right place to start if you don't have a machine yet.

Preparing the car before polishing

Polishing over dirt is rubbing sand into the paint. Preparation is not optional.

1. Wash the car thoroughly. Car shampoo, not washing-up liquid, which strips away whatever protection is there.
2. Decontaminate. Use a clay bar if the paint feels rough to the touch after washing and drying. Particles of tar, iron or resin stay stuck to the surface and washing alone won't remove them.
3. Dry in the shade, never in the sun. A microfibre drying towel prevents water marks that, ironically, you would then try to polish out.

Only once the surface is clean, decontaminated and dry can you see the real defects. And not mistake bonded dirt for a scratch that isn't there.

Protect plastics, rubbers and chrome before you start

Polishing compound is made for the clear coat, not for the black trims, rubber seals or chrome strips around it. On these porous or textured surfaces, the abrasive gets ingrained and leaves whitish marks that are hard to remove, especially on matt black plastic.

Mask off the joins between paint and plastic with masking tape before working near them: window trims, badges, side mouldings, door handles if they're textured plastic. On chrome strips, the risk is different: a cloth or pad loaded with abrasive dragging over chrome can mark it. A strip of tape wide enough to cover the join is enough to avoid both problems.

Step by step: how to apply polishing compound

1. Work in small areas. Around 50x50 cm at a time: a door panel, half a bonnet. On a larger area, the product dries before you finish working it.
2. Use a small amount of product. A little on the pad or applicator is enough for the whole area. More product doesn't speed up the result, it just makes it harder to remove at the end.
3. Cross-hatch movements, moderate pressure. Go horizontally first, then vertically, over the same area, without forcing it. Excessive pressure doesn't speed up polishing, it only increases the risk of marking.
4. Watch the product change appearance. When it turns almost transparent and gets harder to spread, it has done its work in that area.
5. Remove with a clean microfibre cloth, folded, turning to a clean side for each panel.
6. Move on to the next panel only after checking the result under direct, not diffused, light, so the defects show up.

Removing dried compound from corners, trims and rubbers

In tight corners, next to trims, badges and rubber seals, the compound often dries before you can reach it with the large cloth. There's no point forcing the same cloth in there: use a soft-bristled detailing brush to loosen the dried residue without scrubbing the plastic around it.

If it has already dried on a rubber or textured trim, lightly dampen a clean microfibre cloth and dab gently, without rubbing the same spot over and over. Rubbing porous plastic with dried abrasive residue is what leaves those whitish marks that only come off later with a dedicated plastics product.

The water test: how to check it worked

After polishing and before protecting, run clean water over the area you've worked on. On well-polished paint, the water runs off evenly and the gloss stays consistent under direct light, with none of the whitish haze typical of an area that is still oxidised. If you still see water marks drying unevenly, or some areas duller than others, that area isn't ready yet. Go over it again before moving on to the final protection.

Common polishing mistakes

• Using the wrong grit for the defect. Reaching for cutting compound for a fine scratch that Medium would already fix, or trying to correct a deep scratch with Fine alone, which doesn't have the abrasive for it.
• Polishing with the car in the sun or the panel hot. The product dries before it does its work and the risk of marking goes up.
• Pressing too hard. It's the abrasive that does the work, not your arm. Too much pressure increases heat and the risk of holograms, not the speed of the result.
• Skipping decontamination. Polishing over bonded dirt is like sanding with grit trapped in the cloth.
• Working areas that are too large. The product dries halfway through and stops spreading well, which forces you to go back.
• Not protecting plastics and rubbers before starting. Marks on textured plastic are harder to remove than the scratch you were correcting.
• Moving on to wax without doing the water test. You seal in a defect that's still there instead of having corrected it.

The risks of polishing badly

Polishing means removing material from the paint. Done well, it's safe and reversible within generous margins. Done badly, it has real consequences.

• Burning through the paint. Heat concentrated in one spot, especially with a rotary machine on edges or body lines, can remove the clear coat completely and expose the base coat. More compound won't fix that.
• Holograms. Fine web-like marks left by a compound that's too coarse or an unsuitable pad. They can be corrected with a fine finishing step, but that extra step is required.
• Removing too much clear coat. The clear coat has a limited thickness. Polishing several times a year, or working one area too hard, will use up that margin over time. After that, no polish can fix it.

None of this is a reason not to polish. It's a reason to work in small areas, without rushing and without too much product.

After polishing: wax or seal

Polishing compound leaves the paint corrected, but bare. Without a layer of wax or sealant on top, it loses its gloss faster and is exposed again to the rain, the sun and the dirt that made you polish it in the first place. Applying protection straight after polishing, never before, is what completes the job.

Do it yourself or take it to a professional detailer

Doing it at home costs far less and, for touch-ups or fine scratches, gives exactly the same result as paying someone. By hand or with a dual-action polisher, the risk of damaging anything is low if you follow the steps calmly.

It's worth paying a detailer when the car has lots of scratches or holograms spread across the whole bodywork, when it's about to be sold and the finish affects the price, or when the paint is already thin or has been resprayed and the risk of getting it wrong outweighs the money you'd save. A detailer with a rotary machine and experience will sort that out in less time and with less margin for error than a first attempt at home. If you've never used a machine at all, starting by hand or with a dual-action polisher before jumping straight to a rotary is the safest choice.

How often to polish

It's not a regular maintenance task like washing or waxing. Once or twice a year is normal for a car that's used and washed with care. More than that starts to wear away clear coat with no real need. If the paint only needs to keep its gloss between polishes, that's a job for wax, not another pass of compound.

Frequently asked questions

Can I use polishing compound on any car?

Yes, on any paint with a normal automotive clear coat. The exception is paint that is already very thin or has been resprayed several times; in those cases, always test on an inconspicuous area first.

How often should I use polishing compound?

Once or twice a year is enough for most cars. Polishing more than that wears away clear coat with no real gain.

Do I need to apply wax after polishing?

Yes. Polishing compound corrects the paint but doesn't protect it. Wax or sealant is what completes the job and keeps the gloss.

Does polishing compound remove deep scratches, the kind you can feel with a fingernail?

Not safely. A scratch you can feel with a fingernail has already gone through the clear coat; polishing harder to remove it will only thin the paint around it. For those cases there's Redex Scratch Remover, which disguises rather than removing material, or a professional bodywork repair.

Can I polish by hand or do I really need a machine?

By hand works well for spot touch-ups and fine scratches, it just takes more time. To correct the paint on a whole car, a dual-action polisher speeds up the job without the risk of burning through paint that comes with a rotary.

Can I polish the car in the sun?

It's not a good idea. The heat dries the product before it takes effect and increases the risk of marks. Always work in the shade, with the panel cool to the touch.

What's the difference between polishing compound and wax?

Polishing compound corrects. It removes material from the clear coat to erase defects. Wax protects. It sits on top, without removing anything. They are used in sequence, never one instead of the other.

What's the difference between Fine and Medium compound?

Medium corrects visible defects, such as wash scratches and light oxidation. Fine doesn't correct deep scratches; it only removes the holograms Medium leaves behind and gives the final finish.

Does polishing remove paint from the car?

Yes, a minimal amount. That's how it works. The clear coat is thick enough to withstand several polishes over the years, as long as they aren't frequent or done with excessive pressure.

How long does it take to polish the whole car?

By hand, a whole car with Medium compound and then Fine usually takes a full afternoon, done calmly in small areas. With a dual-action polisher it takes less time, but it's still a job of hours, not minutes.