Bava Metzia 52 - Shabbat April 20, 12 Nissan

Can one use money that is devalued? At what percentage would it be considered ona'ah and one can claim back the amount he/she was exploited by the devaluation of the coin? There is a debate between Rabbi Meir, Rabbi Yehuda and Rabbi Shimon. Why is this different from ona'ah with clothing where there is no debate? Once a coin is devalued to more than half its original value, the coin must be destroyed. Why? There is a debate about whether one needs to destroy the coin from the rate of ona'ah until half of its value or just below half its value. Two difficulties are raised against Rav Huna who held by the first option. What is the time frame allotted for getting back the exploited money? Is it the same as for clothing or different? The Mishna mentions an exception to the rule – a case where one can return it even over a year later. How is this case understood by Rav Chisda? A coin that is devalued can be used for redeeming maaser sheni produce. How does this work?