No...there is no "good way" of saying/asking this. The ones you received were rude.

I always get a kick out of everyone that says they "have everything." I have been married 30 years and I still need things!

Anyway....what you need to do is to simply NOT register anywhere. Your guests are smart enough. Once they see that you are not registered, they will (hopefully) give you a card with cash.

It is NEVER good etiquette to mention anything about gifts on an invitation.