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.
Unless there is a stop payment order in effect on the item, Banks reserve the right to pay stale dated (checks more than 180 days old) or post dated (future dated checks). Human eyes rarely look at checks anymore, and the check can, and will slide through the cracks and could cause you overdraft fees.