Q. Dear Rabbi. If someone walks in the street during Shabbat where most people are non-Jewish and he sees a golden bracelet laying in the side walk, (there is an Eruv) can he pick it up and keep it?

A. On questuon 3498 we mentioned:
“Q. I was leaving Shul on Shabbat and I noticed just outside of the steps of our Shul to the street a key ring with keys that had a Jewish symbol attached. Since I’m Machmir and I don’t carry on Shabbat even in our city that has an Eruv, was I permitted to lift the ring to comply with the mitzva of Hashabat Aveida (returning a lost item to it’s owner)?”

To what we answered: “On question 128 regarding Hashavos Aveidah of Muktza items on Shabbos, we questioned: “If the D’oraisa (Biblical command) of returning a lost item override the prohibition of Muktza.” And we answered: Shulchan Oruch (O.C. 266,13) prohibits picking up an “Arnekei” on Shabbes. Biur Halocho (ibid.) forbids retrieval of the Arnekei (money bag) when carrying is an issue (no Eiruv), even if it was found in a place where the majority of residents are Jewish and his intention is to return it to its owner (Hashovas Haaveida).

As far as Muktza is concerned, he declares that it requires further elucidation and refers us to the O.H. (686: 22) and Biur Hagra’ah ibid. dealing on a Shofar manufactured on Rosh Hashono. Mishnah Berura there (82) explains that if there were an issue of Muktza , it would be prohibited to blow the Shofar.

There are Poskim who disagree. however, most maintain that even a mitzva of the Torah does not override Muktza in this and similar cases. (see: Chasam Sofer O.C. 82, Divrei Sholom 17, Mishmeres Sholom Ch. 3, Adonei Shlomo 266, Shmiras Shabbos 236,28).”
In our particular case, one may ask a neighbor that is lenient and does carry in this kind of Eruv to retrieve the lost item in order to return it to its owner.

Horav Shlomo Miller’s Shlit’a opinion is that it is better to kick the keys with one’s foot, until finding a secure place.

Rabbi A. Bartfeld as revised by, Horav Dovid Pam, Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit’a