Translation:Shulchan Aruch/Orach Chaim/21
1. The strings of the tzitzit that have stopped their use [by falling off, tearing off, etc.] may be thrown into the garbage, because tzitzit is a commandment that is not holy for its own sake [i.e. tzitzit are only a mitzvah by virtue of their being attached to a four cornered garment]. However, at all times that the tzitzit are attached to a tallit it is forbidden to use them for another purpose, like to bind them to anything else and so forth, because this would be to scorn the mitzvah (and there are those who say that even after they have stopped their use that we do not treat them scornfully by throwing them into a disgusting place, but that they must be ritually buried in a genizah) (Kol Bo Laws of Shabbat). And there are those who are punctilious to ritually bury them, and for the one who is stringent and careful in the performance of mitzvot, a blessing shall come upon him) (Maharil Laws of Tzitzit)(And see below section 664 paragraphs 8 and 9)).
2. Tallitot [garments] used for the commandment [of tzitzit] that wore out, a person can separate himself from them [and not use them], and one is not permitted to wipe himself with them, and not to designate them for any disgusting use, rather he can throw them away, and they are [like regular] vessels.
3. It is permitted to enter a bathroom with tzitzit. RAMA: And of course to sleep in them is permitted. And there are those that write that it is our custom to not sleep in a tallit that has tzitzit on it, also one shouldn't give it to a non-Jewish cleaner to clean. And everything is so that commandments shouldn't become despised because of it. However, the custom is to be lenient [with regards] to sleeping in them (Kol Bo).
4. There should be caution, when a man wears a tallit that he shouldn't drag his tzitziot.