Halakhah for Shekalim 7:2
מָעוֹת שֶׁנִּמְצְאוּ לִפְנֵי סוֹחֲרֵי בְּהֵמָה, לְעוֹלָם מַעֲשֵׂר. בְּהַר הַבַּיִת, חֻלִּין. בִּירוּשָׁלַיִם בִּשְׁעַת הָרֶגֶל, מַעֲשֵׂר. וּבִשְׁאָר כָּל יְמוֹת הַשָּׁנָה, חֻלִּין:
Money found before (i.e., in the marketplace of) animal sellers is always ma'aser [i.e., even the entire year (and not only on the festival). For the festival pilgrims do not manage to spend all of their ma'aser sheni money on the festival and they leave it with their relatives or close friends to eat the entire year in Jerusalem. And the essential mitzvah of eating ma'aser sheni is (through) peace-offerings. Therefore, most of the beasts sold in Jerusalem all the days of the year are bought with ma'aser money. And even though the money might have fallen from the sellers and already been redeemed, still, since the buyers are in the majority, many people buying from one merchant, we say that it is the buyers' money and was not redeemed, and, therefore, ma'aser.] (If it were found) in the Temple Mount, it is chullin. [Even on the festival, when most of the money that men carry is ma'aser money, still, it is ruled to be chullin, for we rule according to the majority of the year and assume that it fell before the festival.] In Jerusalem [not in the animal market], during the festival, it is ma'aser. [We do not rule according to the majority of the year, for the streets of Jerusalem were swept every day, and if it had fallen before then, it would have been found.] The other days of the year it is chullin. [But the Temple Mount was not swept. For, being high, the wind swept it and removed all of the dust. (Also, it was forbidden to enter the Temple Mount with dust on one's feet, so that dust did not abound there.)]