IFC Chair John McLaughlin says if your pepper spray is more than a year or two old, throw it away!  Even though most pepper sprays have a shelf life of up to four years, real-life testing shows you don’t want to stake your life on an aging product.  The propellant evaporates and valves can start to go bad in just 24 months. McLaughlin is a certified OC/Pepper spray instructor through Agile Training and Consulting.