One who changes for a sela copper coins from second tithe: Beth Shammai says: “Copper coin for the whole sela.” And Beth Hillel say: “Silver for one shekel and copper coin for one shekel.” Rabbi Meir says: “Silver and fruits may not be substituted for silver.” But the sages allow it. Second tithe, the second ten percent of agricultural products, was to be taken to Jerusalem and consumed there. If it was inconvenient to carry all of the second tithe produce to Jerusalem, one could redeem the produce with money and bring the money to Jerusalem. Our mishnah discusses a person who has already redeemed some second tithe and wishes to exchange his small copper coins for a larger more valuable silver coin, a sela, which will be easier to carry to Jerusalem. According to Beth Shammai, in order to do this he must have a whole sela’s worth of copper coin. If he has only half a sela’s worth of copper (=shekel) and he has a silver shekel (=1/2 sela) which is also of second tithe, he may not exchange the shekel and shekel’s worth of copper for a sela since it is forbidden to exchange silver second tithe for other silver second tithe. According to Beth Hillel, one is permitted to exchange a silver shekel and a shekel’s worth of copper coins for a sela. Although it is in general forbidden to exchange silver second tithe for other silver second tithe, since part of this exchange is copper, it is permitted. Rabbi Meir limits Beth Hillel’s opinion. Although it is permitted to exchange silver and copper for silver second tithe, it is forbidden to exchange fruit and silver for other silver. However, the Sages allow even this.