Dave Bonta's short poem is about a private sadness the speaker tries to keep quiet. The title, "Clandestine," sets that up: whatever is felt here is meant to stay secret. The speaker's eyes hold only "a tear or two," a small amount, and even those are "sacrificed" to "things out of sight." The word suggests an offering made in secret, as if the grief has to be paid out to something hidden rather than shown to anyone.
The last two lines turn to the cause. Someone's "parting with me" has left "clutter in my pen," which I read as a sign that the speaker can't write clearly. The feelings are tangled and the words won't come out in order. The poem itself is spare and restrained, which makes a nice contrast with that mess. The mood is quiet and wistful, and the sorrow is held back more than it is displayed. It feels like someone sitting alone, trying to write about a loss and managing only a few fragments.