Diesel Spillage and Odour Removal: Audi

This was an Audi e-tron -- electric car, so no diesel on board. The owner had been doing a favour for someone whose car had run dry, and put a couple of jerry cans in the boot. One tipped on its side during the journey. He did not notice straight away how far it had spread.

Diesel does not stay where it falls. It runs downward, then spreads from the bottom up, working its way into every layer -- carpet, foam sound-deadening, the underlay beneath that, the spare wheel well. By the time we had the rear stripped out, we could see a diesel run in the subwoofer pocket, residue on the back of the centre piece, and contamination under the underlay that had no obvious surface sign at all. The smell when you lifted any of it was unmistakeable. We can tell you -- you could smell it while filming.

Washing the parts had already been attempted. It had not worked. Diesel is a light oil and detergents will break it down and reduce it, but they will not remove the odour from foam and carpet. The foam pieces needed to be replaced -- not expensive, but there is no alternative. The boot carpet we tried to save; if it could not be saved, that would need replacing too.

We advised the owner to notify his insurance company straight away, not to claim but to have it on record. If the boot carpet could not be saved, or if other parts turned out to be beyond cleaning, having a case number already open meant he would not be starting from scratch if costs escalated.

Once the strip-down was done and the parts that needed replacing were ordered, the team UVA-fogged every surface -- glass, metal, plastic -- to decontaminate at surface level. Then we sealed the car and ran a thermo fog through it with Kentucky Blue Grass. Diesel smell is acrid and sharp; Kentucky Blue Grass pairs with it, adding complementary notes that form a new chord. Over time both fade together. The thermo fog is light -- not liquid -- so it reaches the ventilation ducts, under the seats, behind the dashboard, everywhere you cannot get to with a cloth. You watch the fog fill the car and disappear into every gap.

By the time we had finished, there was no evidence of spillage visible and the smell was gone. New parts, clean metalwork, treated surfaces. The car left in better condition than it arrived.