<m.Shabbath 17.5>  

All utensils which may be handled on the Sabbath, their fragments may be handled too, provided, however, that they can perform something in the nature of work. [Thus]: the fragments of a kneading trough [that can be used] to cover the mouth of a barrel therewith, [and] the fragments of a glass, to cover therewith the mouth of a cruse. R. Judah [T4; PA4 or PA5 in Y] maintained: provided that they can perform something in the nature of their own [former] work; [thus:] the fragments of a kneading trough, to pour a thick mass therein; or of a glass, to pour oil therein.

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