You need legal assistance to pull this off, but here is some typically found wording:
You agree that Bank may disregard information on any check or item other than the signature of the drawer, the identification of the drawee bank and payee, the amount, and other information encoded on the MICR line. You agree that Bank is not responsible to take action on, or for failure to notify you of restrictive language placed on checks or other items, including but not limited to terms such as "Void after 90 days", "Paid in Full", "Two Signatures Required", "Void Over $100" or similar statements. In accordance with reasonable banking standards, most checks and other items are processed through automated processing and, except in limited circumstances and in our discretion, most items are not individually examined. You agree that Bank acts within reasonable banking standards by processing most checks and other items through automated processing systems. Bank may agree to adhere to extraneous banking legends if you notified Bank of such legends and Bank has separately agreed in writing to honor such legends.
The opinions expressed are my own, take them or leave them.