The Reaction
Copper reacts with oxygen, moisture, and carbon dioxide in the air. Over years, those reactions build a blue-green surface layer called patina — or verdigris. It is the same coating on the Statue of Liberty.
THE SCIENCE • THE SCRAP VALUE • THE STRAIGHT ANSWER
WHY DOES COPPERTURN GREEN?
That blue-green coating on old copper pipe, roofs, and gutters has a name — patina — and a simple explanation. Here is what it is, why it happens, and the question every seller asks: does green copper still pay?
Patina ExplainedVerdigris ScienceScrap Value AnswerNo Cleaning Needed
THE SCIENCE, PLAINLY SAID
What patina is and why it forms.
Copper does not rust like steel. It goes through its own slow transformation, and the green is the final stage.
The Timeline
Bright copper darkens to brown within months outdoors, shifts through dark tones over a few years, and reaches full green in roughly 5 to 10 years. Indoors, copper can stay bright for decades.
The Protection
Patina is not damage — it is armor. The layer seals the metal beneath and stops further corrosion. That is why copper roofs last a century and old statues stand for generations.
THE MONEY QUESTION
Does green copper still pay?
- Yes — patina is only skin deep. The green layer is microns thin. The copper underneath is unchanged, and that is what gets graded and weighed.
- Color never sets the grade. Buyers grade on the metal itself: bare bright, #1, #2. Surface color — bright, brown, or green — does not move a lot between grades.
- Only real metal loss matters. Deeply pitted or crumbling copper, where actual metal has flaked away, weighs less — and that is about weight lost, not color.
- Do not clean it. Scrubbing, polishing, or chemically stripping patina does not raise the grade or the price. It costs you time and supplies for zero return.
- Pipe, wire, gutters, roofing — all welcome green. Green copper from repipes, tear-outs, and roof replacements grades exactly like its bright equivalent.
- When in doubt, send a photo. A picture of green pipe gets the same firm quote as a picture of bright pipe — usually the same day.
SURFACEPatina is cosmetic
A thin layer that protects the metal beneath it.
VALUECopper is copper
Green or bright, it grades on the metal, not the color.
EFFORTZero prep needed
Send it green. Cleaning adds nothing to your number.
HOLDING GREEN COPPER?
It pays the same. Send a photo.
Old pipe from a repipe, green gutters from a tear-off, weathered roofing copper — it all grades on the metal underneath the patina. No cleaning, no prep, no minimums.
- PHOTOS — The overall pile plus a close-up showing the metal.
- WEIGHT — Your best estimate; we verify on arrival.
- LOCATION — City and state for pickup or freight planning.
COMMON QUESTIONS
Patina questions, answered straight.
Why does copper turn green?
Copper reacts with oxygen, moisture, and carbon dioxide in the air over time, forming a blue-green surface layer called patina (verdigris). It is the same process behind the green color of the Statue of Liberty. The patina actually protects the copper underneath from further corrosion.
Is green copper still valuable as scrap?
Yes. Patina is only a thin surface layer — the copper underneath is unchanged. Green copper pipe, wire, and fittings still grade and sell as copper. Only material that is deeply pitted or crumbling, where actual metal has been lost, might grade differently, and that is about weight lost, not the color.
Should I clean patina off copper before selling it?
No need. Cleaning patina does not raise the grade or the price — buyers grade on the metal itself, not the surface color. Save your time and your cleaning supplies; send the copper as it is.
Does patina mean my copper is damaged?
Not usually. Surface patina is cosmetic and even protective — it seals the metal beneath. Real damage is pitting, flaking, or crumbling, where the metal itself is breaking down. Most green copper from plumbing, roofing, and gutters is perfectly sound underneath.
What is verdigris?
Verdigris is the common name for the blue-green patina that forms on copper, brass, and bronze. Chemically it is a mix of copper carbonates and sulfates built up from years of exposure to air and moisture. It is the same coating on old copper roofs and bronze statues.
How long does it take copper to turn green?
Outdoors it typically takes 5 to 10 years for the full green patina to develop, though the stages start much sooner: bright copper darkens to brown within months, then shifts through dark tones before the green appears. Indoors, copper can stay bright for decades.
GREEN OR BRIGHT
Your copper pays the same. Get a number.
Send photos of your copper — green patina, brown tarnish, or bright and shiny. You will get a firm quote based on the metal, not the color.