Shelf life is 12 months from the date of manufacturing. The date of manufacturing is listed on the top of the cover. The date code will be a 5 digit number. First 2 digits of the sequence of numbers will be the year of production, and the next 3 letters will be the actual day of the year it was made. For example, 10513would mean that this particular batch was manufactured on the 105th day of 2013.
To extend the shelf life, when storing the product, store the can upside-down. This will create an internal seal and will help keep the tape for thickening and hardening over time.
Gardner Bender FAQ 