In short. You can polish an aluminium wheel to a mirror only if the metal is bare. Most original-equipment alloy wheels are covered with a clear coat, and on that coat Kia, for one, forbids "polishing compound". So the first job is to find out what surface you have. On bare, polished aluminium, Alcoa's advice is a non-abrasive aluminium polish worked in small circles with a soft cloth, buffed with a dry microfibre towel, then a sealant or wax made for aluminium. Sanding out scratches or pits removes metal, and the European wheel makers' association (EUWA) lists removing more than 1.0 mm of material from the outer rim flange among its examples of repairs that are not allowed, adding that the figure is no allowance for smaller removals. By our arithmetic, the dry film of one refinish clear coat is only 1.3 to 1.6 grains of P400 paper thick.
First, find out what surface you have
Alcoa Wheels, which makes forged aluminium wheels for trucks, gives the rule in one line (28 October 2025): "Always confirm your alloy wheels' finish type before using any cleaning or polishing product."
| Surface | What it looks like | Polish it? | What the source says |
|---|---|---|---|
| Bare polished aluminium | mirror with no visible grain; dulls and goes milky with time | yes, with a non-abrasive aluminium polish | Alcoa: mirror-polished finishes "benefit from regular polishing" |
| Polished or brushed aluminium under clear coat | mirror or brushed, under a transparent layer | no | Kia: no abrasive cleaner, polishing compound, solvent or wire brushes on the clear protective finish |
| Diamond-cut (machined face under clear coat) | very fine, even rings left by the lathe | no | the same clear coat; see our diamond-cut wheels guide |
| Gloss paint | smooth colour, clear-coated | not with metal polish | Kia, for the clear finish |
| Matte or satin | no sharp reflection | never | Mercedes-Benz: "Never polish the vehicle or the light alloy wheels. Polishing causes the finish to shine." |
| Chrome-plated | very sharp, cold mirror | chrome products only | General Motors treats chrome wheels separately and warns against acid cleaners on them |
| Surface-treated (no visible coat) | bright, no film | no | Alcoa: buffing or polishing removes its Dura-Bright treatment |
Table compiled by the Onyx Forged design office from the sources quoted; our guide to wheel finishes covers the care of each.
Where to look first. The invoice, the wheel maker's product page or the car maker's brochure usually names the finish. Alcoa, for instance, marks its treated wheels with the letters "DB" after the part number and a differently coloured logo sticker (service manual, sections 4.d and 14).
The cloth test, as a last resort. No source we read describes it; it is a workshop habit. Pick a hidden spot, such as the inside of the barrel. Put a dab of aluminium polish on a clean white cloth and rub for a few seconds. If the cloth turns grey or black, you are rubbing bare aluminium: the polish lifts a little oxide and metal. If it stays white or barely tinted, there is a coat between the cloth and the metal. Stop there. Do it once: the test wears the surface slightly. A wheel can be bare in one area and coated in another (Alcoa notes that the inside surface of some of its treated wheels has no treatment), so test the area you mean to polish.
What the wheel and car makers say
- Alcoa separates its mirror-polished wheels, which are uncoated, from its Dura-Bright wheels: "Buffing, polishing, sanding, grinding or other kind of abrasive handling" removes the treatment (section 13.c). For the polished ones, section 14.a says not to use "abrasive products or tools to clean or polish" the wheels, and its 2025 advice adds no steel wool and no abrasive pads.
- General Motors names one failure to watch for on polished or machined wheels: filiform corrosion, "chalky white lines under the clear coating" (bulletin 07-03-10-015C, May 2013).
A trap in the words: a metal polish can contain a very fine abrasive. The ingredient sheet of one metal polish paste sold for a mirror shine lists alumina first, an aluminium oxide used as an abrasive, then water and hydrocarbons. Our reading: "non-abrasive" on a polish for bare aluminium means very fine, not harmless, and on a clear coat even a fine grit wears the finish, which is why Kia rules out polishing compound.
How to polish bare aluminium wheels by hand
This is the simple case: bare metal that has only dulled.
- Work on a cool wheel, in the shade. Alcoa says hot wheels cause spotting.
- Wash with a mild, pH-neutral soap and water. Alcoa rules out harsh acid or alkaline cleaners and hydrofluoric acid; GM says not to use cleaners containing hydrofluoric, oxalic and most other acids "on chrome wheels (or any wheels)". Rinse and dry. Our guide to cleaning alloy wheels covers brake dust.
- Apply a non-abrasive aluminium polish with a soft cloth, in small circular motions (Alcoa, 2025). Work one small area at a time.
- Buff with a dry microfibre towel until the towel stops turning black.
- Protect with a sealant or wax made for aluminium (Alcoa, 2025); bare metal dulls again without it.
- Keep the mounting faces clean and bare. The EUWA wants all contact surfaces of hub and wheel clean with "no foreign object" between them, at the risk of vibration and loss of torque (ES 1.07, section 3.1). No polish or wax there.
If you take the wheel off to polish it, the car stays raised and supported on axle stands, never on the jack alone. Refit the nuts or bolts to the car maker's torque, in a cross pattern, and check them again after a short drive (the EUWA says after about 50 to 100 km, section 3.7): our wheel nut torque guide explains why.
How long does the shine last? We found no figure; Alcoa only speaks of "regular" polishing and regular cleaning.
Dull, scratched or pitted: grits and compounds
When polish alone no longer works (pits, fine scratches, a milky haze that will not shift), you have to sand, then polish. That is no longer maintenance but restoration, and it removes metal. Alcoa approves no alteration of its wheels "except minor cosmetic buffing for appearance purposes", sanding or grinding being permitted only to maintain the rim flanges within its wear limits (sections 5.b and 13.g), and the EUWA lists repairs that are not allowed (see below).
What P400 or P2000 means, and why a US "400" may differ
Abrasive papers sold in Europe and the UK use the P grades of the FEPA 43-1 and 43-2:2006 standards, taken up in ISO 6344. The FEPA publishes the median grain diameter of each grade:
| Grade | Grain diameter (FEPA) | Size against the grade above it in this table | A 45.7 to 55.9 µm clear coat, in grain diameters |
|---|---|---|---|
| P180 | 82 µm (mean, estimated by the FEPA) | 0.6 to 0.7 | |
| P240 | 58.5 ± 2 µm | 0.71 | 0.8 to 1.0 |
| P320 | 46.2 ± 1.5 µm | 0.79 | 1.0 to 1.2 |
| P400 | 35.0 ± 1.5 µm | 0.76 | 1.3 to 1.6 |
| P600 | 25.8 ± 1 µm | 0.74 | 1.8 to 2.2 |
| P800 | 21.8 ± 1 µm | 0.84 | 2.1 to 2.6 |
| P1000 | 18.3 ± 1 µm | 0.84 | 2.5 to 3.1 |
| P1500 | 12.6 ± 1 µm | 0.82 (from P1200, 15.3 µm) | 3.6 to 4.4 |
| P2000 | 10.3 ± 0.8 µm | 0.82 | 4.4 to 5.4 |
| P2500 | 8.4 ± 0.5 µm | 0.82 | 5.4 to 6.7 |
Our calculation, from the FEPA tables (ds50 median values from P240; P500 at 30.2 µm and P1200 at 15.3 µm are left out of the table). The coat thickness is the dry film Axalta recommends for a refinish clear, Spies Hecker 8820: 1.8 to 2.2 mil, or 45.7 to 55.9 µm (1 mil = 25.4 µm). It is not the thickness of the clear on your wheel, which we do not know; it is an order of magnitude.
In the United States, many papers carry a grade with no "P" (the ANSI scale, often called CAMI). The Unified Abrasives Manufacturers' Association warns that grading systems do not line up: its own example is a JIS 600 grit averaging 18.5 to 21.5 microns against 8.3 to 10.3 microns for a FEPA F600. The same number on two papers can mean two different grits. Read the back of the sheet, and keep to one system through a sequence.
Two lessons follow from the table.
On a clear coat, even fine paper goes too far. A clear of that thickness is only 1.3 to 1.6 grains of P400 deep. A scratch is shallower than the grain that cuts it, but on our reading the scale is enough for P400 to break through the clear in places. Once the clear is broken, moisture reaches the metal, which is how the filiform corrosion GM describes starts. A damaged clear-coated wheel is stripped and recoated, not polished: see powder coating or painting wheels.
On bare aluminium, do not skip grades. From one grade to the next in the usual sequence, the grain shrinks to 0.74 to 0.84 of its size. Each paper has to remove the scratches of the one before. Jumping from P400 to P2000 asks a grain 3.4 times smaller to erase scratches cut by one 3.4 times larger. The polish comes last. Kits vary, so read the grades printed on them.
Pitted wheels
A pit is a hole of corrosion in the metal. To remove it by sanding you must take the whole surrounding area down to the bottom of the pit. Our calculation: 1 mm is 1,000 µm, about 29 grains of P400. Erasing a pit or a kerb scratch 0.3 mm deep (about 0.012 in) already removes 30% of the 1.0 mm that the EUWA table lists for the outer rim flange among repairs not allowed, and the EUWA states that its figures are no allowance for smaller removals. At home there is no way to measure the thickness left on a curved flange. Our oxidation guide covers corrosion that has not yet pitted the metal, and our kerb damage guide the limits of DIY kits. Deep pits, kerb damage that catches a fingernail, and corrosion at the tyre bead seat are workshop jobs: our guide to alloy wheel repair says what can and cannot be fixed.
By hand, with a drill or with a polisher: watch the heat
A machine removes metal quickly and heats the surface. Alcoa forbids heating its wheels to straighten or repair them, because the alloy is heat-treated and "uncontrolled heating will weaken the wheel" (section 5.d). Among its examples of repairs that are not allowed, the EUWA lists paint stripping above 160 °C (320 °F) and basecoat and clear coat cured above 100 °C (212 °F) (ES 1.07, table 1). We read no temperature limit for polishing itself. Our precaution: the area you polish should stay comfortable to touch with a bare hand, and a drill-mounted pad never stays in one place.
A wheel that will not shine. Alcoa writes that a wheel exposed to excessive heat (tyre fire, bearing failure, dragging brake) "can show a dull greyish colour and will not polish to a bright finish" (section 13.d), and it takes any overheated wheel permanently out of service. If a bare wheel stays grey whatever you do, stop polishing and have it inspected before you drive on it.
The limits: what the wheel makers do not allow
The EUWA deals with this in section 6 of ES 1.07 (English edition, June 2020):
- "The repair of a damaged rim or disc by heating, by welding, by plastic deformation, by addition or removal of material is strictly forbidden." (6.1)
- "The visual reconditioning of the wheel is possible only one time." (6.4)
- When an outside company reconditions a wheel, "the full liability is transferred" from the wheel maker to that company or to whoever ordered the work, and the company marks the wheel with a hard stamp (6.2 and 6.3).
Table 1 gives examples. For scratches on the outer rim flange, the edge that meets kerbs: "removing material more than 1.0 mm or reworked thickness below than 10 mm", with risks of fatigue cracks, collapse and air loss. For scratches or corrosion on the front of the spokes, remachining is also listed as not allowed, the table defining it as "the use of machining tools, not local grinding". The EUWA adds that the table "is not an allowance" for the repair of other defects or of smaller ones.
Three places you never polish or sand: the faces that bear against the hub (EUWA 3.1); the tyre bead seat, which no text we read mentions but where the tyre seals, so we would not remove metal there (see bead leaks on corroded rims); and anything cracked, chipped deep or bent, which is no longer cosmetic. Have that wheel checked before you drive on it.
Can aluminium look like chrome?
Polished bare aluminium gives a mirror, but it is not chrome. Chrome is a plated layer on top of the wheel, and the makers treat it as a different finish: GM asks for cleaners that state they are safe for chrome and lists acids that attack it, such as hydrofluoric and hydrochloric acid. Flaking or pitted plating is a refinishing job, not a polishing one.
Clear coat after polishing?
Polishing a wheel that is already clear-coated. Do not use metal polish or paper on it: Kia forbids polishing compound on its clear-coated wheels. Wash it with pH-neutral soap, and add a non-abrasive wax or a coating if you wish. A clear that is cloudy, or lifting over white filaments, has failed and is stripped and recoated.
Clear-coating a wheel you have just polished. That is a refinish, and it changes the wheel's future: once coated, you no longer polish it. Read the data sheet of the clear you buy. Axalta's sheet for one refinish clear lists its substrates as basecoats and "fully cured OEM or existing topcoat"; bare polished metal is not among them, so a clear chosen at random may not hold on bare aluminium. That sheet also reserves the product to trained professional painters, since it contains isocyanates: a clear coat over polished metal is a job for a refinisher. The same sheet gives low-bake drying at 43 to 49 °C (110 to 120 °F) metal temperature, well under the 100 °C cure the EUWA cites among repairs not allowed. If you would rather change the colour, our guide to painting rims at home sets out what spray paint and peelable coatings involve. If you prefer to leave the metal bare, protection is the alternative:
| Protection | What it does | What to know |
|---|---|---|
| Wax or sealant for aluminium | protects and makes cleaning easier | redo it regularly; never on the mounting faces (Alcoa, EUWA) |
| Ceramic coating | a thin hard layer on a prepared surface | durability and preparation: our ceramic coating guide |
| New clear coat | seals the metal; no more polishing afterwards | check the substrates on the data sheet; cure temperature matters (EUWA table 1) |
Is there a rule? US, UK, Canada, Australia
We read no law on polishing a wheel on your own car, in any of the four countries. What the official texts cover is the dust, at work. Polishing and sanding aluminium make fine metal dust, and OSHA writes that materials which do not burn in larger pieces, "such as aluminum or iron", can be explosible in dust form. The exposure limits for aluminium metal dust differ:
| Where | Text | Limit (8-hour average) |
|---|---|---|
| United States | OSHA, 29 CFR 1910.1000, Table Z-1 | 15 mg/m³ total dust; 5 mg/m³ respirable fraction |
| United Kingdom | HSE, EH40/2005, fourth edition 2020 | 10 mg/m³ inhalable dust; 4 mg/m³ respirable dust |
| Ontario, Canada | Regulation 833, list updated 26 June 2025 | 1 mg/m³, respirable fraction |
| Australia | Safe Work Australia | not read: the page did not respond when we tried |
Compiled by the Onyx Forged design office on 16 October 2026. Other Canadian provinces set their own limits.
These limits bind employers, not someone polishing in a driveway, and none is a dose to aim for. In practice: wet-sand where you can, work outdoors or with ventilation, wear a dust mask and eye protection, and wipe dust up rather than blowing it about.
Frequently asked questions
Can I polish clear-coated aluminium wheels?
Not with metal polish or sandpaper. Kia forbids polishing compound on its clear-coated wheels because it can scratch or damage the finish. Wash with pH-neutral soap and wax without abrasive; a failed clear is stripped and recoated.
How do I know if my wheels are clear-coated or bare?
Check the invoice or the maker's page first. Failing that, rub a hidden spot with aluminium polish on a white cloth: black on the cloth means bare metal; a clean cloth means there is a coat.
How do I polish aluminium wheels by hand?
On bare metal: wash with mild, pH-neutral soap, apply a non-abrasive aluminium polish with a soft cloth in small circles, buff with a dry microfibre towel, then seal with a wax or sealant made for aluminium (Alcoa).
What grit sequence should I use on bare aluminium?
One without jumps, where each paper removes the scratches of the last. On the FEPA P scale, each usual step shrinks the grain to 0.74 to 0.84 of its size. Check that all your papers use the same grading system.
Can I polish pitted aluminium wheels?
Shallow staining, yes. Removing a pit means taking the whole area down to its depth; on the outer flange the EUWA lists removing more than 1.0 mm among repairs not allowed. Deep pits are a workshop job.
Can I make aluminium wheels look like chrome?
Bare aluminium polishes to a mirror, but chrome is a separate plated layer with its own products. Polishing does not make aluminium into chrome.
Can I use a drill to polish wheels?
Yes, with care: a machine removes metal fast and heats it. Alcoa says uncontrolled heating weakens a wheel. Keep the pad moving and the surface cool enough to touch.
Choosing a finish you want to maintain
On made-to-order wheels, the finish is chosen when you order: bare polished aluminium is polished again regularly, a coated surface is not polished at all. Onyx Forged does not recommend a size or an offset; our wheels are designed to JWL/VIA standards, and the dimensions are those of your car. You can see each finish in the customisation tool.
Sources
- EUWA, ES 1.07, Safety and Service Instructions for the use of Wheels in Tyre Workshops, June 2020 (sections 3.1 and 6, table 1).
- Howmet Wheel Systems, Service Manual for Alcoa Wheels, 2022 edition; Alcoa Wheels Australia, How to maintain that Alcoa Wheels shine, 28 October 2025.
- Kia, owner's manual, aluminum wheel maintenance; Mercedes-Benz USA, 2017 GLS Operator's Manual, matte finish care; General Motors, bulletin 07-03-10-015C, May 2013, published by NHTSA.
- FEPA, abrasive grains and P-grit sizes (FEPA 43-1 and 43-2:2006, ISO 6344); Unified Abrasives Manufacturers' Association, Abrasives 101.
- Axalta, Spies Hecker HS Speed Clear Coat 8820 data sheet, revised May 2026; Dursol, Autosol Metal Polish Super Gloss ingredient datasheet, 12 January 2023.
- OSHA, 29 CFR 1910.1000 Table Z-1 and combustible dust; HSE, EH40/2005 Workplace exposure limits, fourth edition 2020; Ontario, occupational exposure limits under Regulation 833.
All pages were read on 16 October 2026.
The Onyx Forged design office.