I'm rethinking what I said earlier about returning the certificate.
If you thanked them for the gift, that's all you need to do from an etiquette perspective. You are under no social obligation to do anything else. If they ask you about it, all you have to say is "I'm sorry, we just couldn't work out the logistics and the certificate expired."
Understandably, this is not just an etiquette issue. That's where I think the dealing with it head on comes into play.
Heh, I vote for dodging and fibbing - but that's just my low character talking. :)
Thanks... it's good grist for the mill, and we're thinkin' and talkin' on it..... we're loaded up with frap to take the the dump.... see you all in a while.
the certificate is still on the desk ;~D