Before anything else happens to a scrap car, every fluid in it is drained, stored separately and sent for treatment. Fuel, engine oil, coolant, brake fluid and screenwash all come out during depollution at an Authorised Treatment Facility, because even small spills of them do serious damage. Almost all of it is treated and used again.
What comes out, and where it goes
| Fluid | The risk | What happens to it |
|---|
| Fuel | Flammable, pollutes water | Recovered and reused |
| Engine oil | Toxic, persistent in water | Treated and re-refined into new oil products |
| Coolant | Ethylene glycol is toxic to people and animals | Separated and remade into new antifreeze |
| Brake fluid | Hazardous, corrosive | Stored separately, sent for specialist treatment |
| Screenwash | Low, but still controlled | Collected with other washer fluids for treatment |
The scale of the risk is easy to underestimate. The US Environmental Protection Agency puts it starkly: the oil from a single oil change is enough to pollute around a million gallons of fresh water, roughly 4.5 million litres. That is one car's oil, once. It is why draining fluids is the first regulated step of the vehicle recycling process, and why it is never a job for a driveway.
How the fluids are recycled
Most yards do not treat fluids on site. They drain them into sealed, separate containers, and specialist companies collect them for processing. The plants use a range of techniques, from filtration and distillation to reverse osmosis, depending on the fluid and the equipment. Different methods, same goal: separate the useful base material from water, contaminants and anything else that has found its way in.
Antifreeze is the neat example. Reverse osmosis pulls the ethylene glycol out of the waste mix, it is re-dosed with additives, and it goes back on sale as new antifreeze. Cheaper than making it from scratch, and it avoids the gas-hungry process of producing fresh ethylene glycol.
Engine oil follows a similar logic: cleaned, treated and re-refined into new oil products rather than burned or buried. Together with the battery, the catalytic converter and the tyres, the fluids make up the hazardous first wave of removals that has to happen before a car can be crushed.
Why this is worth caring about when you scrap
An unlicensed operator has no obligation to do any of this, and rogue traders still exist. A car that is crushed with its fluids in it puts all of them into the ground. Selling through a licensed Authorised Treatment Facility means the depollution is done, recorded and enforced, and the rest of how car recycling works follows from there.
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Get a quoteUsed oil figure: US Environmental Protection Agency, epa.gov. Depollution requirements as set out under the UK end-of-life vehicle framework. Checked 28 August 2026.
