What happens if you put Used cooking oil in the wrong bin?

Never pour oil or fat down a sink or toilet — it congeals in the pipe and builds fatbergs. Never tip it into a garden; it draws vermin and coats soil. Never mix it into the used engine oil bank.

Where do Used cooking oil go?

Let it cool, seal it in a container, and put it in general waste — or take it to an oil bank.

General waste bin

Cooking oil poured down a sink cools on the way and sets on the pipe wall, and combined with wet wipes it forms the fatbergs that sewer crews cut out of trunk mains. Small household quantities go in a sealed non-recyclable container in general waste; larger quantities from a fryer are better taken to a household waste centre with a cooking oil bank, where the oil is processed into biodiesel. Some food waste collections accept small amounts of oil soaked into kitchen paper, and some do not, which is exactly the sort of thing to check with your own council. Never mix used cooking oil with engine oil — that contaminates a clean waste stream with a dirty one.

How to prepare it

Let it cool completely before moving it.
Pour into a screw-top plastic bottle or a lidded tub.
Wipe the pan out with kitchen paper rather than rinsing it.

What not to do

Never pour oil or fat down a sink or toilet — it congeals in the pipe and builds fatbergs.
Never tip it into a garden; it draws vermin and coats soil.
Never mix it into the used engine oil bank.

Kerbside collection rules genuinely vary by council and county, and local rules always win over general guidance. The reasoning above is what transfers — if your service differs, it will usually be for a reason described here.

Other things that go to general waste bin

Polystyrene and foam packaging General waste almost everywhere. It is recyclable in principle and collected almost nowhere.
Incandescent and halogen bulbs General waste, wrapped. They are not recyclable glass and not electrical waste either.
Crisp packets and snack wrappers General waste, or a supermarket soft-plastics bin where one exists. Not the kerbside recycling.
Broken glass Wrap it thickly and put it in general waste, unless it is a broken bottle or jar — those can go in the glass bin.
Dried-out paint and empty tins Once the paint is solid, many councils take the tin in general waste or as scrap metal. Check yours, because this one genuinely varies.
Cling film General waste. It is excluded even from soft plastic collections almost everywhere.
Till receipts General waste. Thermal paper is coated, not printed, and it should not go in with paper or compost.
Wet wipes and makeup wipes General waste. Never the toilet, whatever the packet says about flushability.
Dog waste Bagged in general waste, or a dog waste bin. Not the food waste caddy, and not the compost heap.
Nappies General waste, bagged. There is no kerbside recycling route for them anywhere in ordinary use.
Cat litter General waste, bagged. Clay litter is not compostable, and cat faeces carry a parasite that keeps it out of the garden.
Medicine blister packs General waste in most places, or a pharmacy collection scheme where one exists.
Greetings cards with glitter or foil Tear off the plain card and recycle that; the glittery part goes in general waste.
Cigarette butts Put it out completely, then bin it. Filters are cellulose acetate plastic, and a live butt starts bin fires.

Common questions

Where do Used cooking oil go?: Let it cool, seal it in a container, and put it in general waste — or take it to an oil bank.
What happens if you put Used cooking oil in the wrong bin?: Never pour oil or fat down a sink or toilet — it congeals in the pipe and builds fatbergs. Never tip it into a garden; it draws vermin and coats soil. Never mix it into the used engine oil bank.

Where do Polystyrene and foam packaging go? General waste almost everywhere. It is recyclable in principle and collected almost nowhere.
Where do Incandescent and halogen bulbs go? General waste, wrapped. They are not recyclable glass and not electrical waste either.
Where do Crisp packets and snack wrappers go? General waste, or a supermarket soft-plastics bin where one exists. Not the kerbside recycling.
Where do Broken glass go? Wrap it thickly and put it in general waste, unless it is a broken bottle or jar — those can go in the glass bin.
Where do Dried-out paint and empty tins go? Once the paint is solid, many councils take the tin in general waste or as scrap metal. Check yours, because this one genuinely varies.
Where do Cling film go? General waste. It is excluded even from soft plastic collections almost everywhere.
Where do Household batteries (AA, AAA, C, D, 9V) go? Shop or manufacturer take-back
Where do Lithium-ion batteries go? Shop or manufacturer take-back
Where do Vapes and disposable e-cigarettes go? Shop or manufacturer take-back
Where do Medicines and tablets go? Pharmacy
Where do Pizza boxes go? Kerbside recycling bin
Where do Leftover wet paint go? Household waste recycling centre

Sources

US Environmental Protection Agency — EPA (Public domain (US Government))

How these figures are compiled and checked