If the bonds are in a safe deposit box which is not rented to you and to which you do not possess the key anyway, and you do not have a letter or other document from your grandmother in your possession saying that she has given you the bonds (which you can collect from a safe deposit box in Bank X in City Y in State Z), you are SOL. The bonds are part of her estate and do not belong to you.
I doubt that any bank or even the Treasury will cash bonds registered in your grandmother's name knowing only the numbers, or even the actual bonds themselves, unless you have a letter in your possession from your grandmother saying that she has gifted the bonds to you. You might be able to follow the procedure for replacing lost US Savings Bonds if
you have a letter and the bond numbers, but now we are getting into legal details that are inappropriate for this forum.
In view of the revised question, I would say that @DJClayworth's comment on the main question is probably the best course to pursue. You could try looking at Form PD F 1048 (available through the TreasuryDirect web site) which allows you to ask the Bureau of Public Debt to re-issue lost or destroyed bonds. But the Form may ask you to affirm under penalty of perjury that all the statements you make on the form are true, and you have stated that the bonds are neither lost nor destroyed, just inconvenient to retrieve, and you don't really need the bonds to be replaced for the purpose of holding them as investments, possibly in your personal safe deposit box, but to cash them in.
Category: Personal Finance