If one converts into a [silver] sela [copper] coins of maaser sheni, Beis Shammai say: [He exchanges copper] coins for an entire sela. But Beis Hillel say: A shekel's worth of silver and a shekel's worth of coins. R' Meir says: We may not deconsecrate silver and produce [of maaser sheni] onto silver, but the Sages permit [this].