If the can is perfectly sealed, it has a shelf life of a year or two. Once the can is openned, it drops to months. And capping it again wont stop that. It will slow down the evaporation tho. The best bet is to run what you can, add stabilizer to a tank of it in the car, and sell the rest. Buy fresh next year. I buy in 5 gall pails. 1 track day is 2 pails...lol.