Martin Lewis, the finance expert behind Money Saving Expert (MSE), has issued a crucial warning to Tesco Clubcard holders regarding the expiration of £17 million worth of vouchers. These vouchers will expire on May 31 at 11:59 PM, prompting customers to take immediate action to utilize their rewards. Clubcard points can be converted into vouchers for various uses, including shopping at Tesco or redeeming with over 100 Reward Partners, potentially tripling their value. To claim a voucher, customers need a minimum of 150 points, which translates to £1.50 in-store. MSE suggests that some customers may extend the validity of their vouchers by partially redeeming them, although this tactic is technically against Tesco's terms. While this method has reportedly worked for some, it carries the risk of being flagged as abuse of the system. Therefore, customers are advised to check their accounts promptly and act before the deadline to avoid losing their rewards.