We are in the thick of summer, cranking the AC and reaching for anything cold. But for thousands of years, people survived blazing heat without a single modern convenience. China's traditional playbook was full of clever, low-tech fixes that kept things bearable. As temperatures keep rising, can these ancient hacks actually be smarter than our energy-guzzling gadgets? / Can you wear last year's sunscreen (12:29)? On the show: Steve, Fei Fei & Yushan