31 C.F.R. § 355.10
What happens if I present my check to the payor Reserve Bank more than six months after the issue date of the check?
If the payor Reserve Bank refuses payment on a fiscal agency check solely because it is presented more than six (6) months after the issue date of the check, a replacement check will be issued if you:
(a) Surrender the original check; and
(b) Executive the required indemnification agreement.