In getting my books, I have been always solicitous of an ample margin; this not so much through any love of the thing in itself, however agreeable, as for the facility it affords me of penciling suggested thoughts, agreements and differences of opinion, or brief critical comments in general. Where what I have to note is too much to be included within the narrow limits of a margin, I commit it to a slip of paper, and deposit it between the leaves; taking care to secure it by an imperceptible portion of gum tragacanth paste. — Edgar Allen Poe on marginalia

The machine, which emits a hissing sound like a steam radiator, uses a nontoxic solution to break down the texture of the gum, and water, which turns to steam, to evaporate the gum — no matter how fresh or old.