dont leave them on the dash board of your truck on a hot day. I did once and the o rings leaked a nice dribble of red fluid on the dash that caused me some awesome feelings of suffocation and near vomiting mixed with watering eyes and that was just from opening the doors.lol.. wiped it down with a cloth and removed the can from the truck coughing and hacking then left the windows open for 3 hours and truck was good as new. then i testfired the rest of the can downwind to see how effective a 2 year expired can of leaky bear spray would be. it fired exactly how it should and coated every thing in the 15 to 20 foot range i was shooting it in. I wonder if the pepper spray loses its potency over time or if they are just worried about potential pressure loss in the can.