Out of cobweb, perhaps, and how large/long does she want it? I assume a square so it can be used as a baptismal wrap later? If so, I would get going as a year might not be enough. A gift of love or are they paying you? I think you need a year, barring nothing happens in the interim. Splendid task, but couldn't that become a chore when there is some pressure? Perhaps you knit faster than I.
No coffee around as someone I knew spilled it on hers when she was almost done. There is The Laundress Stain Remover which basically takes out anything, ion-based.
What does your gut tell you, as in your first reaction upon the question/request? Elation