From what I've read...occasionally some planchets get misplaced in the plating tank and begin to dissolve, thus change the pure copper plating. The resulting coins have a different color than the norm.
As you may already know, brass is an alloy of copper and zinc. If more zinc is introducted into the mixture the color changes as mentioned by ratman4762
Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2026 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited. Contact Us | Advertise Here | Privacy Policy / Terms of Use