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. When you get your monthly statement for July, you can dispute anything on your account for up to 60 days past the date you received your statement.