Why one magnet test can change your price
The most important sorting decision in scrap is one a child can make with a fridge magnet. Iron-based metals stick, most other metals do not, and the gap in price between the two groups is large enough that sorting them apart before you sell can change the result of a whole trip.
The short definition
Ferrous versus non-ferrous at a glance
- Ferrous metals contain iron. Steel, cast iron and wrought iron are the common ones. They are magnetic, they rust, and they are cheap per kilogram because they are abundant and easy to reprocess.
- Non-ferrous metals do not contain iron as their base. Copper, aluminium, brass, bronze, lead, zinc, tin and nickel are the common ones. They resist rust, they are mostly non-magnetic, and they sell for much more per kilogram.
- Stainless steel is the awkward in-between. It is an iron alloy, so technically ferrous, but it is priced separately because it contains valuable alloying elements.
The word ferrous comes from the Latin for iron, ferrum, and that is all it means. If a metal is mostly iron, it is ferrous. If it is not, it is non-ferrous. Everything else about price follows from that.
Five ways to tell them apart
The magnet test
Hold any magnet against the metal. If it sticks firmly, you almost certainly have steel or iron. If it does not stick, you probably have a non-ferrous metal. A decent magnet on a stick makes sorting a large pile fast, and it is the one test every yard uses.
The weight test
Aluminium is roughly one third the weight of steel for the same volume, so an aluminium ladder feels remarkably light next to a steel one of the same size. Copper, brass and lead feel heavy in the hand. If a thing feels surprisingly light and does not attract a magnet, it is very likely aluminium.
The colour test
Scratch a hidden spot with a file or a knife to see the bare metal under any paint or oxide. Copper is distinctly reddish, brass is yellow, aluminium is silver-grey, lead is soft and dull grey, and steel is mid-grey.
The rust test
Steel and cast iron form orange-red rust. Aluminium forms a white or grey powdery oxide. Copper and brass go green or brown. Stainless steel resists rusting almost entirely. If something has been outside for years and shows no orange, it is probably non-ferrous or stainless.
The sound and softness test
Drop a piece on concrete. Cast iron gives a dull thud and shatters instead of bending. Aluminium makes a lighter, higher note. Lead is so soft that you can mark it with a fingernail. None of these is a laboratory test, but together with the magnet they identify most household metal quickly.
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Check live pricesWhy non-ferrous metal is worth so much more
The price gap between the two groups comes from three things.
Scarcity. Iron is among the most abundant elements in the Earth's crust, and iron ore is mined in enormous volumes. Copper, nickel, tin and zinc are much scarcer, and aluminium, while abundant in the form of bauxite, takes a great deal of energy to extract.
Energy saved by recycling. Making new aluminium from ore takes huge amounts of electricity, so remelting scrap saves most of that energy. That makes aluminium scrap especially valuable to smelters. Copper, nickel and zinc have a similar logic, since refining from low-grade ore is costly.
Use in high-value products. Copper is in wiring, motors and plumbing. Aluminium is in vehicles, window frames and packaging. Brass is in fittings and valves. Buyers of these metals are manufacturers paying a premium for consistent quality, not bulk steel mills buying commodity feedstock.
In practice, a kilogram of clean copper can be worth many times what a kilogram of ordinary steel is. The exact ratio changes with the market, so check the gap yourself on the live prices page rather than relying on any rule of thumb.
What belongs in each pile
Typical ferrous scrap
Typical non-ferrous scrap
Ferrous scrap is also graded by thickness and cleanliness: heavy melting steel is thicker and cleaner than light, thin, mixed material, and cast iron is sold as its own category because its chemistry is different. See Cast Iron Scrap Value for how that grade works, and Scrap Metal Terms Glossary for terms such as HMS and shredded.
The edge cases that trip people up
Stainless steel
Stainless steel is an iron alloy with at least around ten and a half percent chromium, and often nickel too. The common grades 304 and 316 are austenitic, which means they are usually non-magnetic or only weakly magnetic, so a magnet may not stick even though the metal is technically ferrous. Other stainless grades, such as 430, are magnetic. Yards usually test unknown stainless with a magnet and a chemical or handheld analyser, because the price difference between stainless and plain steel is large.
Nickel and cobalt
A few non-ferrous metals are magnetic. Nickel is the one you are most likely to meet, since it is a key ingredient in stainless and in some batteries and alloys. If a magnet sticks to something that does not rust and is heavy, it may be nickel-bearing, which is worth a closer look.
Coated and plated items
A steel part with a thin zinc or chrome coating will still stick to a magnet and is still ferrous. Conversely, a brass-coloured fitting might be brass-plated steel and will stick, which tells you it is worth much less than solid brass. When a magnet sticks to something that looks like a non-ferrous metal, it is almost always a plated steel part.
Mixed assemblies
An electric motor, a radiator or a power cable combines several metals in one item. Yards price these as mixed products or dismantle them. If you can safely separate the copper windings or the aluminium casing yourself, you capture the higher value instead of leaving it to the buyer.
Why it pays to sort before you sell
"It is only a few kilograms. Is sorting really worth it?"
For a casual one-off clear-out of ordinary steel, probably not. But even a small amount of copper or aluminium hiding in a steel load is paid at the lower ferrous rate if the yard cannot separate it efficiently. A magnet and ten minutes is usually enough to rescue the higher-value pieces. For anything approaching business volumes, sorting is among the highest-return jobs you can do.
On ScrapTrade, the same logic applies to listings. Listing ferrous and non-ferrous material separately lets the right buyers find each lot and bid for it properly. Mixed lots attract fewer, more cautious buyers and tend to attract lower prices. The listing form asks for category and weight for exactly that reason. See the scrap material category reference for what belongs where.
Safety when sorting
Sorting scrap is simple, but it is not risk free. Wear gloves and eye protection, lift heavy items properly, and watch for sharp edges. Never cut into a sealed container, a gas cylinder or an old fuel tank, because residual fuel and gas can explode. Do not burn the plastic off cable, which is illegal in most places, releases toxic fumes and reduces the value of the copper through oxidation. If an item looks as if it may have been radioactive, such as old instruments or smoke detectors, set it aside and do not mix it with the rest.
Frequently asked questions
Is stainless steel ferrous or non-ferrous?
Technically ferrous, because it is an iron alloy. But many common grades such as 304 and 316 are only weakly magnetic or non-magnetic because of their nickel and chromium content, so the magnet test is unreliable. Stainless is priced as its own category because it is worth considerably more than ordinary steel.
Why is non-ferrous metal worth more than ferrous?
Mainly scarcity and energy. Metals like copper, nickel and zinc are less abundant than iron, and aluminium takes a great deal of energy to make from ore, so recycled non-ferrous material saves more cost and keeps more of its value.
Can ferrous and non-ferrous metal be mixed in one load?
You can bring them together, but a yard will sort them before pricing or pay the lower ferrous rate if the load is too mixed to separate efficiently. Sorting first, even roughly with a magnet, usually earns you more overall.
What is the fastest way to check a large mixed pile?
Walk through it with a magnet and pull out everything that does not stick into a separate pile. It will not be perfect, since coated steel and some stainless can behave oddly, but it takes minutes and splits the load into two very differently priced groups.
Are any non-ferrous metals magnetic?
A few are. Nickel and cobalt are magnetic, and a brass-coloured fitting that a magnet picks up is almost always plated steel rather than solid brass.
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Related reading: How Scrap Metal Recycling Works · How to Grade Your Scrap · Scrap Metal Terms Glossary · Copper Wire and Cable Scrap Price Guide