La Genèse 49:11 Références de la Michna : Mishnah Kelim

The dung bag of a bull and its muzzle, a bee shelf, and a fan are clean. The cover of a small box is susceptible to uncleanness; The cover of a clothes chest is clean. The cover of a box, the cover of a basket, a carpenter's vice, a cushion under a box or its arched cover, a reading-desk for a book, a bolt-socket, a lock-socket, a mezuzah case, a lyre case, a violin case, the block of the turban-makers, a wooden musical toy horse, the clappers of a wailing woman, a poor man's parasol, bed posts, a tefillin mould, and the mould of string makers all these are clean. This is the general rule which Rabbi Yose stated: all objects that serve as a protection to objects that a man uses, both when the latter are in use and when they are not in use, are susceptible to uncleanness; but those that serve them as a protection only when the latter are in use are clean.