Teflon is a remarkable substance. It has the best resistance to chemical attack of any polymer, and it can be used at any temperature between -73 C and 260 C with no effect on its properties. It also has a very low coefficient of friction.
A stale dated warrant is an unredeemed warrant which was issued more than six months prior to the current date. A stale dated warrant is expired and the original instrument is no longer negotiable.
The last digit is always 7 but they are new and this is 08. As a buyer of a lot of food I will say that if I buy a bag in Feb. of this year and it has a date of May 20 it is usually stale after that date of this year.