I've heard from a few places (including one of my friends college professors :thumbsup that as long as it's stored in an airtight container in the freezer, it's good for up to a year.

In anticipation of finding a job after college I stopped on May 1st and was clean for 63 days before I broke over the July 4th extended weekend. I tested clean the day I broke so I vacuumed sealed a clean sample incase it was needed. I havent smoked now in 10 days and will probably get tested next week if a job prospect works out. I'm nervous but I think aslong as I follow the guidelines for flushing I found on here I should be cool.