3,114. A Linen Thread Lost in a Wool Garment (or Vice Versa)

Hilchos Kilayim 10:26

One may carry on his shoulders a corpse or an animal that is wearing shaatnez.

Hilchos Kilayim 10:27

If a linen thread gets lost in a wool garment, or if a wool thread gets lost in a linen garment, the garment may not be sold to a non-Jew out of concern that he might resell it to a Jew. One may not make a donkey’s saddle blanket with it out of concern that someone else might come across it, remove it from the saddle blanket and wear it, because the shaatnez in it isn’t apparent. Here’s what should be done: the garment should be dyed. This helps because wool and linen don’t dye the same way. In this way, the stray thread will become apparent and he can then remove it. If it’s still not identifiable, the garment is ruled permitted on the assumption that the stray thread fell off. This is because the garment was checked and the thread wasn’t found. It was already discussed in Hilchos Issurei Biah that doubts in such prohibitions are of a rabbinic nature, with the result that the Sages ruled leniently in cases of doubt.