A few days ago I was walking to a class in TABC and I noticed an empty lost-and-found bin. I was then reminded of a sweatshirt I lost last year. When I went to inspect the lost-and-found bin over the summer for the sweatshirt I was told it was emptied out after the last day of school.
I began to wonder what exactly the Halachot of lost-and-found are. If I see someone else wearing my sweatshirt can I claim it and demand its return? Furthermore, did the wearer of said sweatshirt do anything wrong in wearing it? Should he have done something else with it first?
Let’s begin by defining ‘lost.’ While it may seem tedious, there are two types of ‘lost’ that are actually extremely important to define in Halachah. An item is truly lost if the original owner has no hope of finding the item. For instance, if one loses something in a foreign country that he or she will never return to, then that item would fall into this category of truly lost. In the Gemara the owner would be referred to as having Yei’ush (lost hope in finding the item).
However, another type of ‘lost’ exists. If I lose my phone inside my house, for example, I likely haven’t lost hope of finding it, as its presumably not very hard for me to find. In other words, there is no Yei’ush.
If something has a clear identification - Simanim - then there is no Yei’ush and the item must be returned. An example would be a wallet with a driver’s license inside. However, if you find something such as money which has no sign of identification, then you can keep it without making a lost-item announcement (editor’s note: the amount of money lost may constitute a Siman and thus it is worthy of making a lost item announcement to the effect of “An amount of money has been found). Additionally, no one can claim that it is theirs. Moreover, if a lost item is found in a place in which it would be hard to retrieve, (such as a river) then Yei’ush is applied as well.
Besides for the positive commandment to return a lost item, there is also a negative commandment “Lo Tuchal LeHitaleim,” “not to turn a blind eye” from a lost item (Devarim 22:3). Everything more than approximately 25¢ (one estimation of the current value of a Perutah), or within approximately 6-7 feet is included in this Mitzvah.
Finally, a peculiar item with a blatant Siman (sign), such as an engineering project, or something which is placed in a secure location like a locker does not fall under the Halachic principle of Yei’ush and need not be returned.
In conclusion, whoever has my Nike sweatshirt can keep it… I gave up hope of finding it months ago.