The blue-greenish stuff is oxidation known as verdigris. It can be removed by using a chemical wash called Verdicare, which can be purchased from a CCF member named BadThad (PM him if interested).
Your coin also has some dark staining, which cannot be removed.
Is your coin worth holding onto? Only you can answer that question, but your coin has damage and will (most likely) never worth more than one cent.
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