Yes, you can use dry ice to turn your cooler into the ultimate deep freeze. All of the hard-sided Pelican Elite Coolers are designed with a gap in the gasket that acts as a pressure release. This makes your cooler easier to open, and also allows the carbon dioxide gas to escape the cooler as the dry ice sublimates. It is important to keep the dry ice from direct contact with the cooler in order to prevent damage to the cooler itself. A folded towel, layer of cardboard, or even a few paper grocery bags should be enough to protect your cooler and give you the best performance! In the image below, we used two layers of grocery store paper bags placed on the bottom of the cooler.  We kept the dry ice in the packaging we bought it in and then placed it on top of the paper bags. Next, we placed another two layers of paper bags on top and added a good layer of regular ice to create a deep freeze.Remember to use dry ice safely!Do not handle dry ice directly. Use protective gloves or oven mitts when handling dry ice.Ventilation is a must! Roll down your car windows to avoid a dangerous buildup of carbon dioxide gas.Most importantly, DO NOT use dry ice in Pelican soft coolers. These coolers are designed to be leak-proof and the buildup of gas inside them could cause an explosion.