Miss Manners: If you return a present, do you mention that in the thank-you note to the gift-giver?

DEAR MISS MANNERS: My fiancé and I are getting married this fall. It will be a very small wedding, with just our immediate families in attendance, and no formal reception. Because we are having such a small wedding, and because we have been living and creating a home together for the past six years, we did not create any kind of wedding registry. The attendance of our loved ones at this special moment is gift enough!
However, my MIL-to-be recently hosted a surprise wedding shower on our behalf, where several relatives who will not be at the wedding gave us gifts. While we are so grateful for their thoughtfulness, our lack of a registry meant that several of the gifts were either not our style or things we already had. The guests did provide gift receipts, so we were able to return some of these unneeded items and purchase a nice knife set instead.
How should I complete the thank-yous for the items we returned? Do we mention that they were exchanged for something else, or just thank people for what they gave?
I don’t want to lie and say, “Thank you for the candlesticks; they have a prominent place on our mantel!” when that is not the case.
GENTLE READER: Welcome to a world where presents are not just chosen off of a list and some thought is put into their choosing. Isn’t it wonderfully tacky?
Being honest would be cruel, but outright lying is not necessary, either. Miss Manners suggests that you compliment the presents without committing to using them. As in: “What a unique and interesting tablecloth. Its Jackson Pollack-like look will be so convenient in hiding spills.”
** ** **
(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, [email protected]; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)