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The basic split
Ferrous metals contain iron: mild steel, cast iron, wrought iron, most structural and sheet steel. They are magnetic, they rust, and they are cheap per kilo but move in enormous volume.
Non-ferrous metals contain no significant iron: copper, aluminium, brass, lead, zinc, nickel, and their alloys. They do not rust in the familiar orange way, they are generally not magnetic, and they are worth many times more per kilo.
Stainless steel sits awkwardly between the two. It contains iron, so it is technically ferrous, but its chromium and nickel content give it a value far above ordinary steel, and the trade prices it with the non-ferrous metals.
The magnet test, and where it fails
Carry a magnet. It is the fastest sorting tool there is, and it is right most of the time.
- Strong pull — mild steel, cast iron, ordinary structural steel.
- No pull — copper, brass, aluminium, lead, zinc.
- Weak or partial pull — this is where it gets interesting.
The exception worth knowing. Not all stainless steel is non-magnetic. The austenitic grades — 304 and 316, the ones used for sinks, kitchen equipment, food vessels and tanks — are essentially non-magnetic. The ferritic and martensitic grades, the 400 series used for cutlery, blades and some automotive trim, are magnetic.
So "the magnet stuck, therefore it is only mild steel" is a genuinely expensive mistake. People sell 430 stainless at mild steel rates fairly regularly. If a magnetic piece looks too bright and clean for ordinary steel, and shows no rust despite obvious age, look again.
Work-hardening also matters: heavily formed 304 — the deep-drawn corner of a sink, a tightly bent edge — can develop a slight magnetic response even though the sheet is genuinely 304. A faint pull at one spot with none elsewhere usually means exactly this.
Identifying the non-ferrous metals
Copper
Unmistakable when clean: a distinctly reddish, salmon colour. Aged copper goes brown, then green. It is heavy — noticeably heavier than it looks — and soft enough to scratch with a knife, showing bright pink metal underneath.
Copper is graded, and the grades are far apart in value. Bright bare wire is the top; heavy clean tube and busbar next; then general copper with solder, paint or fittings attached; then insulated cable, priced on the recoverable copper inside rather than gross weight.
Brass
Yellow, sometimes with a reddish or greenish cast depending on the zinc content. Copper alloyed with zinc. Taps, valves, fittings, locks, ornaments, cartridge cases. Heavy, and harder than copper. A scratch shows yellow, not pink — that is the quickest way to separate brass from a copper piece that has darkened with age.
Bronze — copper and tin — looks browner and duller. Bearings, bushes, marine fittings, statuary.
Aluminium
Light. That is the giveaway: about a third the weight of steel for the same size, and you can feel it immediately. Dull silver-grey, non-magnetic, soft. Window frames, ladders, cookware, extrusions, engine castings, cans, foil.
Clean extrusion is the best grade. Cast aluminium is a step below. Anything with steel bolts, plastic thermal breaks or rubber seals still attached gets discounted for the labour of stripping it.
Lead
Very heavy, dull grey, and soft enough to mark with a fingernail. It will leave a grey streak on paper. Batteries, sheet, weights, some old plumbing and cable sheathing.
Lead-acid batteries are handled separately and are subject to their own rules on collection and disposal — they are not general scrap, and a legitimate buyer will treat them accordingly.
Zinc
Bluish-grey, notably brittle. Die-cast parts, galvanising residues, older carburettor bodies. Middling value.
Stainless steel
Bright, does not rust, heavy, and harder than mild steel. The magnet test above tells you which family it belongs to. 304 and 316 are worth appreciably more than the magnetic 400 series, and a serious buyer will test rather than guess.
Relative value, and why it differs so much
We will not print rates — metal prices move daily with global exchanges and any figure here would mislead you within a week. But the relative ordering is stable enough to be useful. Taking mild steel as the baseline:
| Metal | Roughly, relative to mild steel | What drives it |
|---|---|---|
| Mild steel / iron | 1× | Abundant, cheap to produce new |
| Zinc / lead | Several times | Scarcer, narrower demand |
| Aluminium | Several times | Recycling uses a small fraction of the energy of smelting new |
| Stainless (304/316) | Higher again | Nickel and chromium content |
| Brass | Higher still | Mostly copper by weight |
| Copper | Highest of the common metals | Constrained supply, universal demand |
The reason aluminium holds its value is worth understanding, because it explains the whole industry. Producing aluminium from bauxite is extraordinarily energy-intensive. Remelting aluminium scrap uses a small fraction of that energy. So recycled aluminium is not a second-rate substitute — it is straightforwardly cheaper to make, and metallurgically identical. The same logic applies to copper.
Steel is different. It is recycled at enormous scale, but new steel is cheap enough that scrap steel will never command a high per-kilo price. Ferrous scrap is a volume business.
Mistakes that cost real money
- Selling mixed metal as one lot. A mixed load gets priced at close to its worst component, because the buyer carries the sorting cost and the risk. Twenty minutes with a magnet is usually the best-paid twenty minutes of the whole transaction.
- Assuming magnetic means worthless. See the 400-series stainless point above.
- Leaving copper inside things. Motors, transformers and alternators contain windings worth far more than the assembly's scrap weight. Whether stripping them yourself is worth it depends on volume — but you should at least know it is there, and say so.
- Throwing away insulated cable offcuts. Cable is priced on recoverable copper. Offcuts accumulate faster than people expect.
- Letting aluminium sit outside. It does not rust, but it does oxidise and collect dirt, and heavily oxidised aluminium is downgraded.
Never burn cable to recover copper. It is illegal, it produces genuinely dangerous fumes, and it damages the copper — burnt wire is downgraded on sight. Mechanical stripping is worth more and does not poison anyone.
Have metal to move?
We buy ferrous and non-ferrous scrap across Thiruvallur and the surrounding towns, and we will tell you what a mixed load contains before we price it. Photographs and a rough weight are enough to start.