CO2 Safety - Take extra precautions using CO2 inflators on Presta valves that have replaceable cores. The drastic pressure drop as the CO2 leaves the cartridge super-cools the cartridge and the adapter. In damp weather, this can freeze the adapter to the valve. And when you unscrew the adapter, you end up extracting the valve core with it, deflating the tube you just inflated. Argh! To prevent this, use this trick: After inflation, squirt the valve with some water from your water bottle to de-ice things and then carefully remove the adapter from the valve.