To spot and exploit a player who is overvaluing weak hands, pay attention to their betting patterns. They tend to bet or raise in situations where their hand should be weak or unlikely to improve. These players often overcommit with hands that don't have strong potential or bluff excessively. You can exploit them by playing more aggressively, especially with hands that have good equity against a wide range of weaker hands. You might also want to slow-play your strong hands to induce bets or calls from them, as they will often continue with inferior holdings. Identifying their tendencies to overvalue weak hands allows you to adjust your strategy by applying pressure and capitalizing on their poor hand valuation.