The bumpers, over-riders, lamp rims and grille slats of a T-type are chrome-plated steel, not solid metal — a thin, bright, hard skin of chromium over layers of nickel and copper on a steel base. Understanding that structure is the key both to caring for the brightwork and to knowing the difference between a problem you can wipe away in ten minutes and one that needs a plater.
Owner photograph to follow
Surface rust is not pitting
The single most useful thing to learn is to tell these two apart, because they have completely different causes, timescales and cures.
Surface rust — a fine, even bloom of tiny dark or orange specks, sometimes called “freckling” — sits on top of sound chrome. It can appear in a matter of days, and the chrome beneath it is still bright and mirror-like. It is almost always a moisture problem rather than a plating problem, and it polishes off.
Pitting is plating that has already failed. Where the thin chrome and the nickel beneath it have cracked or worn through, moisture reaches the steel, which corrodes, expands and leaves tiny craters. It develops over months and years, not weeks. Polishing lifts the surface staining but cannot restore lost metal — the pits remain, and in a strong light the surface looks stippled or rough rather than smooth. Deep or widespread pitting, dull grey patches, or flaking are the point at which polishing stops being enough.
A quick test: run a fingertip lightly over the area. Smooth under a haze of specks is surface rust; a fine, sandpaper-like roughness is pitting.
Why a cover can be the culprit
It surprises people, but a cover over a car kept outdoors in warm, humid weather can cause more corrosion than it prevents. On a cool night the metal drops below the dew point and moisture condenses on it; a cover then holds that dampness against the surface instead of letting the morning air dry it. A run of muggy summer nights, or the first rain after a dry spell, is a classic trigger for a bloom of surface rust — especially on chrome, which conducts heat well and cools quickly.
The lesson: a dry garage is kinder to brightwork than any cover. If a car must live outside, cover it only when it is completely dry, use a breathable cover (never plastic-backed, which traps moisture), and on dry nights consider leaving it uncovered rather than sealing dew against the metal.
Cleaning: a light hand wins
For a light bloom on sound chrome:
- 01
Wash and dry the area first
Wash and dry the area first, so you are not grinding grit into the surface.
- 02
Work a chrome polish with a soft cloth
Work a chrome or metal polish — Autosol (Solvol Autosol) and Peek are the long-standing favourites — over the surface with a soft microfibre cloth and light pressure. This alone clears most surface rust.
- 03
Use gentle chemistry on stubborn spots
For stubborn spots, gentle chemistry beats brute force: a soft cloth with a little WD-40, or the old tricks of cola or a cut potato (both mildly acidic), worked gently and then wiped clean and dry.
- 04
Keep abrasives off failing plating
Scrunched aluminium foil dipped in water, and the very finest 0000-grade steel wool with plenty of oil as a lubricant, are traditional and effective on solid, sound chrome — but they are abrasives. On chrome that is already pitting or failing they can wear through more of the thin plating and expose fresh steel, so keep them off the rough areas and reach for polish instead.
Protect it — the step most people skip
Cleaning removes today's rust; protection stops next month's. Once the chrome is clean and bone dry, seal it with a wax — Renaissance Wax (a microcrystalline, museum-grade wax that is superb on brightwork) or a good carnauba paste. The wax keeps moisture off the surface and out of any small pits. On a car stored outdoors, re-wax the brightwork every month or two; on a garaged car, a couple of times a year is plenty.
When to re-chrome — and what it involves
Re-chroming is the only true cure for pitting, because the only way to fill the craters is to add and re-work metal. Consider it when a piece is deeply or roughly pitted, has dull grey areas where the plating has broken down, or is flaking.
Proper restoration chrome is triple plating: the stripped, polished steel is first plated in copper, which is soft enough to be polished back to fill and level the pits; then nickel, which provides most of the corrosion resistance and the depth of shine; then a thin, hard, bright layer of chromium on top. Skipping the copper-and-polish stage is why cheap chrome looks bright at first but soon shows the old pits through it.
Two practical points. First, small parts — over-riders, lamp rims, a single bumper “nub” — are far cheaper to re-plate than a whole bumper, so a badly pitted corner needn't mean a big bill. Second, freshly plated chrome is noticeably brighter than aged chrome next to it, so it is usually worth doing a matched set (both over-riders, say) rather than one, or the repair will stand out. A specialist classic re-plater is the person for the job; the MG Car Club T-Register and the marque forums are the best source of a recommendation and a realistic price.
The verdict for a driven car
On a car that is used rather than shown, a degree of light micro-pitting on the brightwork is honest age, not a fault to lose sleep over. Clean it gently, wax it, sort the storage so the bloom stops returning, and keep an eye on it. Save the re-chroming for the pieces that have genuinely gone rough — and do those on your own timetable, not in a panic.
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This guide is a general introduction and is not a substitute for the official Workshop Manual for your car.