Interiors, where a car shows its age

A vacuum and a wipe-down is a clean. An interior detail is a different job, and most of it happens in places you cannot photograph.

The vacuum goes under the seats, along the rails, into the seat-back pockets and through the boot including under the floor. Seats often come forward on their runners, because the worst of what a car accumulates is in the six inches nobody reaches.

Carpets and fabric get hot water extraction. Hot solution is injected into the pile and drawn straight back out with the dirt suspended in it. That is the stage that separates a detail from a clean, because it lifts contamination out rather than moving it around or pushing it deeper.

Steam handles the vents, switchgear, seams, seat stitching, seatbelt webbing and the gaps around the centre console. It cleans and sanitises without soaking anything, which matters near electronics.

Then leather is cleaned and conditioned, trim and dash are finished matte, and the glass is done last so nothing lands on it afterwards.

A full interior on a neglected car takes the better part of a day, and on a seven-seater with kids in it, sometimes longer.

Spraying scent over a smell achieves nothing except a car that smells of two things. Odour almost always has a physical source, and until it is removed the smell returns within days.

The usual suspects

Spills that reached the underlay. Milk and soft drink are the two that cause real trouble, because they soak through the carpet into the padding beneath, where surface cleaning never touches them. The fix is extraction and genuine drying time, not more product.

A damp cabin filter. Cheap, easy to overlook, and a very common cause of a musty smell that appears when the fan comes on.

Microbial growth in the air conditioning. The evaporator sits in a dark, damp place and grows things. It is the classic cause of a smell that hits you for the first thirty seconds of a drive and then fades as you stop noticing it.

Smoke. The hardest, because it permeates the headlining, which is the one surface that cannot be aggressively cleaned without the adhesive letting go and the lining sagging. It is improvable and honestly not always fully removable, and we will say which before you spend.

We find the source and treat it. If the cause is underlay, the answer is extraction and drying time, and rushing that just traps moisture and creates a second problem.

Being straight about this saves everyone disappointment.

Usually comes out completely: most food and drink spills, mud, general traffic grime, pet hair, and the grey wear pattern down the middle of a driver’s seat.

Usually improves a great deal: older set-in stains, sunscreen on leather and plastics, light dye transfer from denim onto pale seats.

Often permanent: bleach or chemical marks, ink that has been sitting for months, heavy dye transfer into light-coloured leather, cigarette burns, and anything that has damaged the fibre rather than sat on it. A burn is a hole, and no cleaning fills a hole.

Age matters more than severity. A dramatic spill dealt with in a week usually comes out. A small one left for two years often will not.

Most modern car leather is pigmented, meaning it has a coloured topcoat and a clear finish over the hide. You are cleaning that finish, not the leather itself, which is why the aggressive products sold for furniture are wrong for a car.

We clean with a pH-appropriate product and a soft brush that lifts dirt out of the grain, then condition. What we do not do is apply a silicone dressing that looks wet for a fortnight and dries the hide underneath while you admire it. A properly conditioned seat looks matte and feels supple, not shiny.

The bolster on the driver’s seat is where leather fails first, because you slide across it every time you get in. Cleaning and conditioning slows that considerably. Once the topcoat has actually worn through to the colour beneath, that is a repair rather than a detail, and we will tell you which you are looking at.

Alcantara and suede. Increasingly common on steering wheels and seat centres, and easily ruined. It must not be soaked, and it needs brushing back to lift the nap rather than wiping, which flattens it into a shiny patch that does not come back.

Piano black trim. Beautiful for a week and a magnet for fingerprints and fine scratches. It cleans up well and, on badly marked panels, can often be polished much like paint.

Headlining. Cleaned gently and never saturated. Too much moisture releases the adhesive and the lining sags, which is an expensive way to remove a small mark.

Screens. Cleaned with the correct product only. Household glass cleaner will strip the anti-glare coating off a touchscreen permanently.

Seatbelts. Drawn out fully, cleaned along their length and left extended to dry. They are filthy on almost every car and almost never cleaned.

Ultraviolet is what actually kills an interior in Sydney. Dashboards go first, then door tops, then leather, and the damage is cumulative and permanent. A faded, cracked dash cannot be brought back the way paint can be corrected.

Trim protection with UV inhibitors slows it considerably, and it is worth reapplying rather than treating as a one-off.

The larger lever is window tinting. Quality film blocks the overwhelming majority of UV, which is why the strongest argument for tinting is not the heat you feel but the interior you stop destroying. On a car parked outside, the two work together.

Roughly the same shape on every car. What changes is how long each stage takes.