MICROSCRAPPINGE-waste field guide
Other · Tier D

Transformers, inductors, chokes & toroids

Ferrite is heavy, black and worth exactly nothing. You're paying to haul rock to get at a third of a pound of copper.

Cu 100–220 g/lb
eBay typical$15–60per lb
Refiner pays$0.6per lb
Metal in it$1.60per lb at 4 Aug 2026 spot
Confidencemedof the yield figures

How to spot it

Board transformers are EI or ER stacks in bobbins with tape and varnish. Common-mode chokes are toroids with two symmetrical windings right at a power inlet. SMD power inductors are shielded black or grey cubes marked 4R7 or 100. Big painted toroids in yellow, green or blue are power-factor or filter chokes.

Metal content

MetalQuantityNotes
Copper100–220 g/lbwinding copper is roughly 20–35% of a board-level magnetic; ferrite and steel are the rest

At 4 Aug 2026 spot prices that works out to $1.60 per pound of contained metal — Copper 150 g = $1.60. A refiner paying $0.6 returns about 37% of that, which is normal: refining costs money and the buyer takes a margin.

Safe removal

Working temperature: Hot air 380 °C with preheat

Large iron or hot air at 380 °C with board preheat — these have huge thermal mass and thick pins. Recovery means cutting the windings free: crack the ferrite with a hammer, or burn the varnish off outdoors and unwind.

Hazards

💨 Fumes, ventilation and open flame

NEVER burn boards, wire insulation or plastic. Ever.

🪚 Fibreglass and board dust

NEVER dry-cut boards indoors without extraction.

☠ Lead — dust more than fume

NEVER dry sweep or use compressed air on a scrapping bench. HEPA-vac or wet-wipe only.

🧲 Neodymium magnets

Don't let two magnet plates snap together across your fingers.

Before you scrap it

Identifiable switch-mode transformers, Coilcraft and Würth parts, and large iron-powder toroids for RF and audio DIY sell $2–10 each — always more than the copper.

The common trap

A pound of mixed magnetics contains about $1.60 of copper and takes real work to liberate. Yards buy them in the low-grade bin at $0.20–0.50 per pound. Small SMD inductors are worse — nearly all ferrite.

Questions

How much gold is in transformers, inductors, chokes & toroids?

Copper: 100–220 g/lb. At current spot that is about $1.60 of contained metal per pound.

How do you identify transformers, inductors, chokes & toroids?

Ferrite is heavy, black and worth exactly nothing. You're paying to haul rock to get at a third of a pound of copper.

How do you remove transformers, inductors, chokes & toroids safely?

Large iron or hot air at 380 °C with board preheat — these have huge thermal mass and thick pins. Recovery means cutting the windings free: crack the ferrite with a hammer, or burn the varnish off outdoors and unwind.

Is transformers, inductors, chokes & toroids worth more working than as scrap?

Identifiable switch-mode transformers, Coilcraft and Würth parts, and large iron-powder toroids for RF and audio DIY sell $2–10 each — always more than the copper.

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