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.
RE: ff: Most checks are stale dated after 6 months, unless specified by the check. IE: Not valid after 90 days or something similar. However, say for instance you wrote a check in December of last year and the person you wrote it to just cashed it yesterday.