website says that their bonds no longer earn interest after the maturity date, so they won't be worth a ton of cash. You may want to start at the official savings bond certificate website to see if you can get some info on what they're worth. For bonds that old, you'll probably need to get someone on the phone: https://www.csb.gc.ca/2019/06/redeeming-your-certificated-bonds/

If they have nominal cash value as a debt instrument, then start googling the certificate name and see what they're selling for as collectibles.