In the 1980s, several manufacturers produced certain tape formulations blending polyurethane and polyester as backing material which tended to absorb humidity over many years in storage and partially deteriorate. This problem would only be discovered after an archived tape was opened and required to be played again, after possibly a decade or less on the shelf. The deterioration resulted in a softening of the backing material, making it gooey and sticky which quickly clogged-up tape guides and heads of the reproducer. This phenomenon is known as "Sticky-Shed Syndrome" and can be temporarily reversed by baking the tape at a low temperature for several hours to dry it out and restore firmness. The restored tape may then be played normally for several days or weeks, but will eventually return to a deteriorated state again.