They [who consumed terumah] may not pay with leket, with shich'chah, with pe'ah, or with ownerless produce; and not with maaser rishon whose terumah has been removed, and not with maaser sheini or consecrated produce that have been re-deemed, because holy property cannot [be used to] redeem holy property. [These are] the words of R' Meir. But the Sages permit [paying] with these.

R' Eliezer says: They [who consumed terumah] may pay from one type [of produce] for [terumah of] another type, provided that he pays from superior quality [chullin produce] for inferior-quality [terumah]. But R' Akiva says: They cannot pay other than from one type [of chullin produce] for the same type [of terumah]. Therefore, if one ate gourds from the year before Shevi'is, he must wait for gourds from the year following Shevi'is and pay with them. From the place that R' Eliezer [learns to be] lenient, from there R' Akiva [learns to be] strin-gent, for it is stated (Leviticus 22:14): “He shall give to the Kohen the holy”, — [connoting] anything that is fit to be holy. [These are the] words of R' Eliezer. But R' Akiva says: “He shall give to the Kohen the holy,” — [means] the holy that he ate.