Poof coins are made a proof by the polishing of the dies. They can be distinguished from normal circulation coins by their sharper rims and design.
Dies for making modern proof coins are often treated with chemicals for the purpose of giving certain parts of the design a frosted appearance and making the polished fields taking on a mirror finish. There can be several other methods used to achieve this effect. Other methods used in the past include sand blasting the dies. Proof coins of the early 19th century may appear to be scratched, but it was in fact part of the proof coin production process.
Typically proof coins are double struck for improving their high finished appearance.
Proof coins should never be handled with bare hand as it will deteriorate the finish and reduce its value. Proof coins are normally purchased in a protective sleeve and it should not be removed from this protective lining.
Proof coins are normally purchased for their investment value and stored in a secure place for safe keeping.
Books and bygones carry a fair selection of proof coins as well as great range of interesting and valuable circulation coins.