Letter 12249

Pennies 

What is the reason for pennies oxidizing and turning green? What kind of agent would you need to clean copper? What is in the juices used to clean pennies (what causes the juice to clean the acid?)

Kim H.
- Houston, Texas

Please see our FAQs, Kim.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Ed. note: Sorry, but for every metal finisher in the world there are a thousand students, and we are drowning under variations on this question which we've answered hundreds of times already. It's time for the students to read our F.A.Q. on the subject rather than to keep asking us to answer the question for them individually