They didn't use carbon-14. "Groucutt and the rest of the team used a number of dating methods to confirm the likely age of the Al Wusta finger. For the finger

They didn't use carbon-14. "Groucutt and the rest of the team used a number of dating methods to confirm the likely age of the Al Wusta finger. For the finger itself and the tooth of an ancient hippopotamus found nearby, they applied U-series dating. Like radiocarbon dating, the method works by looking at radioactive decay in the preserved materials. The age of the sediments around the bones was calculated using optically stimulated luminescence—a technique that reveals the last time rocks and sand were exposed to sunlight."