Yes, metal belongs in the recycling bin, and two machines decide what actually gets recovered. An overhead magnet pulls steel up out of the stream, and an eddy current separator makes aluminium jump: spinning magnets induce a current in the metal and physically throw it over a gate into its own chute. Every household rule follows from those two facts. A can with liquid in it is too heavy to jump. Flat foil cannot carry the current, so it never jumps at all. And stainless steel responds to neither machine.
Once you can picture the two machines, you can predict every rule on your council’s list without reading it.
The two machines
Steel is pulled. A powerful magnet hangs above the moving belt and lifts ferrous metal straight up through everything piled on top of it, carrying it away on its own belt. This is why steel is the most reliably captured material in the whole plant: the machine reaches into the pile and takes it.
Aluminium jumps. Aluminium is not magnetic, so it needs the stranger machine. At the end of a belt, a rotor of magnets spins at high speed inside the pulley. As aluminium passes over it, the changing field induces an electrical current inside the metal itself, and that current creates its own magnetic field, which pushes against the rotor’s. The piece is launched forward, clearing a divider that everything non-metallic simply falls short of.
Manufacturers rate modern eddy current units above 97 percent recovery on beverage cans in good conditions, and the ferrous magnets run ahead of them by design, because a chunk of steel reaching the spinning rotor can wreck it.
That is the entire system. Now watch each rule fall out of it.
Why every rule exists
| Item | What the machines see | Outcome | The rule it creates | |
|---|---|---|---|---|
| Measurement | How each common metal item behaves at the two machines | |||
| Empty drinks can | Light, conductive, launches cleanly | Recovered | Cans belong in the bin | |
| Can with liquid | The liquid outweighs the repelling force | Falls short, lost | Empty it first | |
| Crushed can | Slips through the sizing screens before reaching the rotor | Ends in glass or residue | Do not crush for kerbside | |
| Loose flat foil | Wrong shape to carry a current | Never launches | Ball foil to fist size | |
| Steel food tin | Lifted by the magnet through the pile | Recovered | Tins belong in the bin | |
| Loose bottle caps | Below screen size, fall through early | Lost | Pinch them inside a can | |
| Stainless cutlery | Barely magnetic, poor conductor | Invisible to both machines | Take stainless to a yard | |
| Wire and hangers | Wraps around shafts and screens | Stops the plant | Never in the bin | |
| Frying pan, pipe, tools | Heavy enough to damage the rotor | Refused | Yard material, not bin material |
The crushed can line deserves its own note, because it surprises people. Sorting screens size material early in the plant, and a flattened can behaves like a flat piece of scrap rather than a container. Facilities have documented losing 60 to 80 cans a minute this way, and several large plants have retrofitted second and third eddy current units onto their glass and residue lines, recovering around 15 tons of aluminium a month that was escaping. Crushing is for deposit-state redemption by weight, not for a kerbside bin.
The stainless line explains a loss nobody suspects. Grades 302 and 304 sit in an awkward middle: too weakly magnetic for the overhead magnet, too electrically resistant to launch. A stainless fork in a kerbside bin reaches the end of the line untouched by either machine.
What the captured metal is worth
The economics behind the machinery are on our live board.
An empty drinks can weighs about 14 grams, which holds roughly 2.7 cents of aluminium at today’s price, and a steel food tin a little over a cent of steel. Neither justifies a journey, and both are exactly what the plant is built to catch, which is why the bin is the correct route for packaging even on a site devoted to selling metal.
The boundary sits at density. A bag of cans is packaging; a box of pipe fittings, a frying pan collection or a broken microwave is scrap, and a yard pays for it by the pound, as our scrap value index prices item by item. The magnet test still settles the grade at the counter: it separates steel from stainless and aluminium in your hand exactly as the overhead magnet does at scale.
Aerosols, lids and the awkward cases
- Empty aerosol cans are accepted by most programmes, steel or aluminium, with the cap off and nothing left inside. Punctured or partly full ones are a hazard at the compactor, covered with the other pressure vessels in our gas cylinder guide.
- Foil trays follow the foil rule: clean, and crumpled together rather than flat.
- Foil with food baked on fails on contamination before shape even matters.
- Metal lids from glass jars are fine loose only if they are above screen size; smaller ones do better pinched inside a can.
- Paint tins go dry and empty or to hazardous waste, never wet into a bin.
- Batteries are not metal packaging and never travel with it, for the fire reasons on our electronics hub.
Where this fits
What the recovered aluminium and steel are worth in twelve markets is on the table below, and the wider question of which stream any item belongs to sits on the recycling hub. The deposit-state alternative, where a can is worth five to ten cents instead of two, is compared in recycling plastic bottles for cash.
| Market | Local price | USD per lb | Market factor |
|---|---|---|---|
| Turkey | ₺96.67 / kg | $0.90 | 1.04 |
| Germany | €1.68 / kg | $0.89 | 1.02 |
| United States | $0.87 / lb | $0.87 | 1.00 |
| China | CN¥12.63 / kg | $0.85 | 0.98 |
| Canada | C$1.17 / lb | $0.84 | 0.97 |
| United Kingdom | £1.36 / kg | $0.84 | 0.96 |
| Australia | A$2.53 / kg | $0.83 | 0.95 |
| United Arab Emirates | AED6.69 / kg | $0.83 | 0.95 |
| Saudi Arabia | SAR6.69 / kg | $0.81 | 0.93 |
| India | ₹167 / kg | $0.80 | 0.92 |
| Bangladesh | ৳207 / kg | $0.77 | 0.88 |
| South Africa | R26.02 / kg | $0.74 | 0.85 |
How we produced this
The machine descriptions come from equipment manufacturers’ published documentation and from materials recovery facility case studies in trade press, including the documented can losses through sizing screens and the retrofit recoveries. The full-can and foil failure modes are stated in an equipment guide published by a recycling trade magazine, and the stainless behaviour in the same manufacturer literature.
Can and tin values are calculated from our own live board prices, documented on the editorial policy page, and refresh daily with the board. Recovery percentages are manufacturer ratings under specification conditions rather than guaranteed plant performance.
Acceptance details for aerosols and lids differ by programme, and your council’s list is the one that applies to your bin.
Frequently asked questions
Can you recycle metal in the kerbside bin?
Yes, and metal packaging is the most reliably captured material in the plant. An overhead magnet lifts steel out of the stream and an eddy current separator physically launches aluminium into its own chute, with modern units rated above 97 percent recovery on cans.
Why do cans need to be empty?
Because aluminium is recovered by being thrown. The eddy current machine induces a current that pushes the can over a divider, and the weight of any liquid inside exceeds that repelling force, so a part-full can falls short and is lost.
Should I crush cans before recycling?
Not for a kerbside bin. Sorting screens size material early, and a flattened can slips through with the glass and residue before it ever reaches the aluminium machine. Facilities have documented losing 60 to 80 cans a minute this way. Crushing is for deposit-state redemption by weight.
Why does aluminium foil need to be balled up?
Shape. Flat foil and wire cannot carry the induced current efficiently, so the machine cannot launch them. A fist-sized ball of clean foil behaves like a can and recovers; loose sheets never do. Food-soiled foil fails on contamination first.
Why is stainless steel refused in single-stream recycling?
It is invisible to both machines. Common grades are too weakly magnetic for the overhead magnet and too electrically resistant for the eddy current to launch, so a stainless fork travels the whole line untouched. Stainless goes to a scrap yard instead.
What do I do with loose bottle caps and jar lids?
Anything below screen size falls through early and is lost. Pinch small steel caps inside a steel can so they travel as one large object. Larger jar lids can go loose where your programme accepts them.
Are aerosol cans recyclable?
Empty ones, yes, in most programmes, steel or aluminium alike, with the cap removed. Partly full or punctured aerosols are a hazard at the compactor and belong with hazardous waste collection instead.
When does metal stop being bin material and become scrap?
At density and size. Packaging belongs in the bin. Pans, pipe, tools, appliances and anything heavy enough to damage a spinning rotor belongs at a yard, which will also pay for it by the pound.
What is a drinks can actually worth?
A few cents of aluminium at board prices, and a steel tin holds a little over a cent of steel. Neither justifies a journey, which is why the bin is the correct route for packaging, while a deposit state pays five to ten cents per container for the same can.
Why do magnets run before the aluminium machine?
Protection. The aluminium separator has a rotor of magnets spinning at high speed inside its pulley, and a chunk of steel reaching it can crush the rotor cover, while even small ferrous pieces accelerate wear. Every plant removes ferrous first by design.