This question has been kicking around for several days so I sent a letter to the Halifax consulate:
I understand that if I have a Certificate of Loss of Nationality I may have to present it when entering the United States.
1) Is it acceptable to present a notarized copy of it instead of the original?
2) If a copy is not acceptable is it possible to get official copies from you in case of damage to the original?
3) If official copies are available could you please tell me the cost and the procedure for obtaining such?
I got back this response:
Thank you for your e-mail.
Once a certificate of loss of nationality is approved by the Department, a copy is forwarded to the United States Immigration and Naturalization Service (USCIS), Department of Justice and a copy of the certificate is also forwarded to the person approved for the Certificate of Loss. It is always suggested that you carry a copy of the certificate with you to help facilitate your entry into the U.S. and maintain your original in a safe place.
Should you lose or damage your original certificate only the Department of State can issue you a duplicate. You can contact the Department of State, 2100 Pennsylvania Ave NW, Washington, DC 20037, to obtain information and/or procedures on how to acquire a duplicate or replacement copy of Form DS-4083, Certificate of Loss of Nationality, DS-4083.
I hope you find this information useful.
I think it’s a relief to know that a copy is sufficient for border crossing purposes – but now I think I’d carry my passport, a copy of the CLN *and* a copy of this email with me!