| Clue | Source | Date |
|---|---|---|
| Unusual change | New York Times | 02 Mar 2024 |
| 1955 doubled die pennies, e.g. | Premier Sunday | 10 Dec 2023 |
| Significant change | Newsday | 13 May 2023 |
| Numismatist's collection | Eugene Sheffer | 25 Oct 2022 |
| Change of value? | Wall Street Journal | 01 Sep 2022 |
| Numismatist's collection | New York Times | 26 Jan 2018 |
| Numismatist's collection | ||
| 1943 copper pennies, e.g. | ||
| Indian Head pennies, etc. | ||
| Collectors' items. |