The poem is built in two halves that clash. The first is a warm, gushing letter to someone the speaker calls "amorcito." They describe waking up thinking of the person's brown eyes, which they find more beautiful than any blue or amber pair, and the way one eye twitches when the person laughs hard. Their body reacts with joy and nerves: bones that "sing," a racing heart, flipping stomach. They even joke about being a clown for feeling so much. Underneath it all is a hope that one day they'll see that love returned.
Then the final lines, in lowercase and with a flatter tone, undercut everything. The letters are never opened. They're shredded and thrown away, and the speaker still tapes the pieces back together. The title, "Ancient Artifact," fits that act of saving fragments. The mood shifts from sweet and hopeful to sad and self-aware, as the speaker admits to feeling "pathetic" while unable to let go.