Are old US proof sets and mint sets worth keeping or selling?

Mint sets contain regular coins from each mint for the year, packaged by the US Mint, while proof sets contain specially struck coins with mirror-like surfaces made for collectors. Both were made in large numbers for decades, and honestly, many sets from the 1970s through today sell for close to what they originally cost or a little more.

The sets that bring more are usually older ones, especially proof sets from the 1950s and early 1960s, and any sets with silver coins. Proof sets dated 1964 and earlier have 90% silver coins, and special silver proof sets from later years also have silver content. A few modern sets include scarce varieties or errors that collectors look for.

Keep each set in its original packaging and box with any certificate, since sets taken apart lose value. Look up the year and type, check sold prices for the same set, and expect most to sell as a group. A coin dealer or auction company can tell you quickly whether any sets in a collection stand out.