Pesachim 19 - A needle in the meat
We mentioned earlier the extra love for the Temple sacrifices, which made the Sages decree additional impurity on such materials, thus forcing the people to be more careful. In discussing this, Rabbi Yochanan mentions that even non-edible parts of sacrifices, such as spices and wood block, can become ritually impure. Moreover, if they are placed in a vessel, the vessel combines them, so that if a ritually impure person touches one component, they all become impure. However, Rav Chanin objects and says that it was not the Sages who decreed it, but the Torah: when it mentioned a sacrifice of "one cup," Rav Chanin interprets this to mean "cup makes all one."
Also on a tangent, the Talmud discusses a needle that was found in sacrificial meat, with the result that the meat is impure, but the hands and the knife are pure. How could that be? Why would we presume that the needle is impure? - We are forced to say that it touched a dead person, and was now recognized by someone. Then the knife should also be impure! In truth it is not, because they only suspect that this is the same needle, and all suspicion of this sort are disregarded in a public area - which the Temple Courtyard surely is.
Art: Woman and Child Doing Needlework by Camille Pissarro