Am I using chocolate-box correctly?

Question

I want to describe the behaviour like when I pay attention to a thing, I care about it, I don't want to lose it, I'll carry it wherever I go, and I'll angry if someone throw that thing away.

I found this word when I was looking for the synonyms of sentimental. The antonym itself is unsentimental, so I think I've chosen this word correctly. According to Merriam-Webster, chocolate-box means:

superficially pretty or sentimental.

Can I use that word like in this conversation?:

A: I broke your pencil, let me throw the pencil away. I'll buy a new one for you.

B: No way! Put it back! It was a gift from my late father.

A: Oh sorry. But it's broken.

B: I know. I'm just chocolate-box.

But that sounds super awkward!

Answer 1

As a native speaker, I've never heard that expression, so it sounds very awkward to me too. I think it might apply better to objects like sentimental pictures than to people, as in the etymology from your linked definition:

History and Etymology for chocolate-box
from the pictures formerly commonly seen on boxes of chocolates

Answer 2

In the early-mid 20th century, assorted chocolates were a small luxury and were sold in shallow cardboard boxes with a lid on which was printed the kind of picture expected to appeal to women, such as flowers, kittens or an idealised country cottage. Chocolate-box describes this kind of sentimental art, not a person's sentimental feelings.

Answer 3

Others have explained well why this isn't a correct use of "chocolate box" so I won't reiterate that, but I believe that the term you're looking for is "sentimental value".

In your example: "B: I know, but it has sentimental value"

This can describe anything that you're emotionally attached to.