Determine whether the old bill is in a good enough condition to offer for redemption. The U.S. Treasury declares that it will redeem old bills that are still at least halfway intact. More than half of the bill must be visible and non-mutilated. Due to this ruling, most banks will redeem old bills for you, as retail bank locations usually send old bills in bulk to be replaced.
Check to see if the old bill is worth any money by searching for the printed date on online auction sites and numismatist enthusiast websites. If the bill was printed before 1970, there's a good chance that a collector will pay more than its face value so long as it's in relatively good condition.
Contact local bank branches and ask if they will redeem old bills. The vast majority of banks process a great deal of old bills for redemption, and most will offer the service as a courtesy. Don't pay any fees to redeem an old bill. The Treasury Department offers bill redemption free of charge.
Bring your old bill to a retail bank location and ask for it to be redeemed. You don't need to have an account at a bank to redeem old bills. Alternatively, you can mail your old bill for replacement to the Office of Currency Standards by using Registered Mail, Return Receipt Requested. Wait to receive the redeemed bill in the mail if you sent it to the Treasury Department.