Bava Kamma, Chapter 10, Mishnah 10 - the final Mishnah in the tractate. The subject of the Mishnah is a person who hires a craftsman to do work for him, when the craftsman works in his own workshop and requests that the raw materials be provided to him: the one ordering a suit provides the craftsman with the fabric, and the one ordering a table provides him with the wood. The craftsman produces the suit or the table, and the question before us is: is he obligated to return the leftovers to the customer, or is he permitted to keep them for himself?
The rule emerging from the Mishnah:
The central principle of the Mishnah, and this is how the halachah is ruled, is that the accepted custom determines the matter. If it is the way of people not to be particular about the leftovers - the craftsman is permitted to keep them for himself; and if they are particular about them, the owners do not waive their rights and do not give up hope of recovering them, and therefore the craftsman is obligated to return not only the finished product - the suit or the table - but also all the scraps and wood remnants. For this reason, the Mishnah states precise measurements, based on the accepted standards of its time.
Fluff that the launderer and the wool-comber remove:
"Muchin shehakovas motzi - harei eilu shelo" - 'Muchin' are the small pieces of wool that come out of the garment during laundering, when a person gives his wool garment to the launderer and he takes it to the river or the laundering place. The launderer is permitted to keep these small pieces and remnants for himself, since the owner of the garment waived his rights to a small amount of wool and does not want it returned (similar to the lint that accumulates in a dryer filter).
"Veshehasorek motzi - harei eilu shel baal habayit" - The one who gives the wool garment for combing, which is a sort of gentle processing of the garment, removes a more significant amount of wool from it. While this is not a large amount in and of itself, since all the crafts were done at home, if the owner would receive these pieces and remnants each time, after ten times he would accumulate enough to make something new. Because of this, he is particular about them and wants them returned.
The launderer's threads:
"Hakovas notel sheloshah chutin, vehen shelo" - When the launderer takes a new garment and washes it for the first time to prepare it for use, he removes the loose threads at the edge of the garment. The tailor usually adds a few threads along the edge of the garment, as can be seen at the edge of a tallis, where the warp and woof threads are located that hold everything together so the garment does not unravel. During the final processing, the launderer removes those loose threads that do not belong to the main body of the garment, and he is permitted to keep them for himself, since the owners do not need these small threads.
"Yeseir miken - harei eilu shel baal habayit" - If he removed more than three threads, the one who hired the launderer wants them too, in order to use them another time. It turns out that if there were three or fewer - they all belong to the launderer; and if there were more than three - everything goes back to the owner.
"Im hayah shachor al gabei halavan - notel es hakol vehen shelo" - If the garment is white and the threads are black, the launderer takes all the dark threads for himself even if there were more than three, since a person has no interest in them.
The tailor's leftovers:
"Hachayat sheshiyer min hachut kedei litpor bo" - The tailor who was supplied with thread and was left with a remnant, the matter depends on its size: if a thread remains that can be used to sew something else, meaning it is twice the length of a needle, the owner is particular about it and wants it returned.
"Umatlis shehi shalosh al shalosh - harei eilu shel baal habayit" - The scraps of fabric that are cut when the tailor or seamstress makes the suit or dress: if their size is three fingerbreadths by three fingerbreadths, a small square, they are fit to serve as a patch for a hole in socks or trousers, and therefore the owner wants them.
It turns out, therefore, that this thread that is longer than two needles and this fabric scrap that measures three by three fingerbreadths return to the customer, along with the dress or suit that was made for him.
The carpenter's leftovers:
Even regarding carpenters who work in their own workshop, we are dealing with wood that was supplied to them by the customer, and not with their own wood - for if it were their own wood, it is obvious that all the leftovers would be theirs. But when the customer supplied the logs of wood and hired the carpenter to make him a table, the question is which leftovers return to him. The rule is that the owner is only particular about the significant pieces:
"Ma shehacharash motzi bema'atzad - harei elu shelo" - The pieces of wood shaved off at the end of the work using a plane, thin chips and bits of wood that have no use other than for kindling, remain with the carpenter, since the owner has no interest in them.
"Uvachashil - shel ba'al habayit" - The pieces of wood removed with an axe when turning a log into a table, which are larger and certainly fit for kindling and similar purposes, are returned to the homeowner. This was undoubtedly the situation during the time of the Mishnah.
If he was working at the homeowner's premises:
In everything stated above, the assumption is that the work is being done in the craftsman's workshop, and he is sweeping his own floor. However, "Im hayah oseh etzel ba'al habayit - af hanesoret shel ba'al habayit" - when the work is carried out in the employer's home, such as when the carpenter is brought to the house, keeping the leftovers does not bother the homeowner at all, since they are already right there in his house. Therefore, he wants to keep all the wood scraps and small pieces for reuse, and even the sawdust, which he will save for the next time oil spills, or similar situations. It emerges that the carpenter is not allowed to take any materials from the homeowner's house to his own workshop, even including sawdust, but must rather leave everything in its place, since the homeowner, who is not troubled by the matter, is particular about keeping all the leftover remnants from the production.
Practical Halachah: The matter is determined according to customary practice, meaning the standard expectations and understandings between craftsmen and employers, in the time and place where the halachah is being applied.
And with this, with Heaven's help, Tractate Bava Kamma is concluded. God willing, next in line is Tractate Bava Metzia.