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Where you meet it: Acid peroxide (HCl + H₂O₂), nitric acid, aqua regia

What you need to know

The chemistry works. The hazards are real and routinely underestimated.
Aqua regia evolves chlorine gas, nitric oxide and nitrogen dioxide. NO₂ is the killer: delayed-onset lung injury — you feel fine for hours, then develop pulmonary oedema overnight. This needs a fume hood, not a garage with the door open.
Never store aqua regia in a stoppered bottle — gas evolution builds pressure and ruptures closed containers. Make it fresh, use it immediately.
Never add organics — acetone, alcohols, detergents, plastics — to aqua regia. Explosion risk.
Always add nitric to hydrochloric, never the reverse. Always acid to water, never water to acid.
Dissolving base metals generates enormous volumes of NOx and heat. A "small" batch can gas out a whole shop.
Then there's the waste: heavy-metal-laden acid liquor that is illegal to drain, expensive to neutralise, and hazardous to store.
If you proceed anyway: certified fume hood or scrubbed outdoor setup, splash goggles plus face shield, acid apron, butyl or heavy nitrile gloves, eyewash and safety shower within ten seconds, a bicarbonate neutralisation plan, and never work alone.

The rule: The practical answer for nearly everyone: sort, concentrate, and sell to a licensed refiner. A good refiner recovers 85–98%, assays rather than guesses, pays on the assay, and takes the waste liability. Your edge as a scrapper is identification and sorting — not chemistry.

Components this applies to

Laboratory Platinum Ware Other · $20000–32000/lb Pt ~454 g/lb — it is solid metalAu 5% in Pt-5%Au XRF fusion cruciblesBase Rh 5–10% in Pt-Rh crucibles S Noble Thermocouple Wire (Type R/S/B) Other · $18000–31000/lb Pt ~410 g per lb of bare noble wireBase Rh 6–30% of one legBase Type K/J/T/E/N: zero PGM S Precious-Metal Sputtering Targets Other · $32000–50000/lb Au ~454 g/lb — the target is solid metalPt 138 g in a 2 in × 0.125 in discPd 77 g in a 2 in × 0.125 in disc S Silver-Oxide Button Cells Other · $40–120/lb Ag ~30–35% by weight ≈ 150 g/lbBase Zn anode ~25%Base LR/AG alkaline S Ceramic CCD/CIS Image Sensors ICs & chips · $150–400/lb Au 0.02–0.15 g per ceramic package ≈ 1.8 g/lbAu under 0.001 g per mobile/webcam moduleBase Nd-Fe-B in VCM actuators A X-Ray Film & Spent Fixer Other · $1–4/lb Ag 0.07–0.10 ozt/lb (2.2–3.1 g/lb) medical filmAg 0.15–0.25 ozt/lb industrial NDT filmAg 1–6 g/L in spent fixer B Gold-Plated Flex Circuits (FFC/FPC/ZIF) Contacts & relays · $10–40/lb Au 0.05–0.15 g/lb of cableCu ~100 g/lbBase 60–80% polyimide/PET + acrylic D Vintage Home Computers & Boards Boards · $80–350/lb Au 0.05–0.20 g per C64 board; 0.1–0.4 g per Apple II boardAu gold-lid ceramic DIPs at $150–400/lbCu ~40 g/lb D

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