דברים יד:כא מקורות במשנה: Mishnah Demai

The [second tithe of] demai is not subject to [the rules of adding a] fifth. It has no mandated time of removal. It may be eaten by an onen. It may be brought into Jerusalem and taken out again. They may allow a small amount to be lost on the road. One may give it to an am haaretz and consume its equivalent in Jerusalem. [Second tithe money of demai] may be redeemed silver [coins] for [other] silver [coins], copper [coins] for [other] copper [coins], silver for copper, and copper for produce, provided that the produce is again redeemed for money, the words of Rabbi Meir. But the sages say: the produce itself must be brought up and eaten in Jerusalem.