
Proof coins
The U.S started minting proof coins as far back as the 1850s through very few were made. Philadelphia made the first proof sets and coins, but in 1968 it switched over to the San Fransisco mint. Some do not have a mintmark and can be very valuable. They started making sets in 1936 which was more than 85 years ago. As seen in one of the pictures, most sets have a certificate of Authenticity (Shout out for Mike) Keep your coins in cases!