For a baby gift, someone gave us a silver baby spoon. I know it's meant to be a keepsake but where do I put it? Plus, I've been personalizing my thank you cards to what people give us and I don't know what to say, please help me fill in the blank. "thank you for the baby spoon ____________"

Re: What do I do with a silver spoon?
Love, luck, and prayers to my BFPB Dr. SnowflakeBride
For the thank you, I would say something like:
". . . It's such a nice/beautiful/special keepsake."
I totally agree. We got a silver spoon, cup, and bowl at my first shower. They are really pretty but, I don't see myself mixing up rice cereal in a silver baby bowl.
My mom gave us a silver spoon and rattle and I adore it. She put them in little wooden boxes (keepsake boxes). Which is what I would suggust. She actually went above and beyond and had them padded and then tied her silver spoon, my silver spoon and LO's silver spoon with ribbons on the pillow padding. She also put all three of our rattles in a different box with padding. Maybe this could be a future keepsake idea for you and your LO.
ETA: A lot of people get them inscribed with birth info and you could also do some sort of shadow box frame with that in there along with footprint, handprint stuff...all kinds of things.
My mom gave us the sterling silver spoon, cup and porridge bowl that I used as a baby. I don't know that she used the cup much, but she did feed me my cereal out of the bowl with the spoon. I say use it. It isn't hard to hand wash a bowl and a spoon and it won't tarnish much with regular use.
Once I got much older, the porridge bowl was in my room holding potpourri.
DH has a silver cup from when he was a baby, and I have silver bracelet. We'll probably just put them on display in LO's room. They're more for show than anything.
We got a child's spoon and fork set in our wedding pattern from DH's aunt and uncle. Betsy can use them (when she's old enough) whenever we break out the silver for ourselves--holidays, etc.
My TY note went something like this: What a special gift--I know that Betsy will appreciate having this heirloom to pass down to her own children.
The one I received is an beautiful and old family heirloom. I like the OP's shadow box idea....
This, they are meant to be used. They are unbreakable, not issues about plastics, and they are elegant. The rattles make me nervous BUT I totally use the silver spoon and cup that we have.