I read that as grits, not gifts.
This doesn't qualify for the thread, but the one time I got a gift I didn't like, I sold it a couple hours later (yes, there's a story behind that). So I guess I could say something like:
1) Is it very valuable?
2) What is it?
3) I hope you can return this.
4) How neat - I have one just like it already.
5) Is this edible? Because I don't accept anything that's not expensive, not fattening, or good for me.
6) What a coincidence - I saw the same thing at a Goodwill store the other day.
7) I'm too old for this.
8) I'm too young for this.
9) You do know that chocolate
is always welcome, right?
10) I had to limit my Christmas wish list to just one thing this year and unfortunately, this isn't it.
and as a bonus:
11) The dog will really appreciate this one!