Bava Metzia 52A

שמונה פונדיונות, שני פונדיונות לדינר.

The accepted depreciation is 8 pundeyon, which is a rate of two pundeyon per dinar, or 1/6th of a dinar.

עד מתי מותר להחזיר? בכרכים ⁠– עד כדי שיראה לשולחני, בכפרים ⁠– עד ערבי שבתות. אם היה מכירה ⁠– אפילו לאחר שנים עשר חדש מקבלה הימנו, ואין לו עליו אלא תרעומת.

The Mishnah continues: Until when is it permitted for one to return a worn coin once he realizes that it is defective? In the cities [bakerakim], one may return it only until a period of time has passed that would allow him to show it to a money changer, who is an expert in matters of coins. In the villages, where there is no money changer, one may return it only until Shabbat eves, when people purchase their Shabbat needs. Although these are the limits of how much a coin must be eroded in order for there to be exploitation, if the one who gave the coin to the aggrieved party recognized it, he must accept it back from him even after 12 months have passed no matter how little the erosion affected its value. And he has only a grievance against him, as the Talmud will explain.

ונותנה למעשר שני ואינו חושש, שאינו אלא נפש רעה.

And one may give the slightly eroded coin for use in the desacralizing of second-tithe produce and he need not be concerned, as one who would refuse to accept a slightly eroded coin is merely a miserly soul, while the coin is in fact valid for any use.

גמ׳ ורמינהי: עד כמה תהא הסלע חסירה ויהיה בה אונאה?

Talmud: And the Talmud raises a contradiction to the Mishnah from a baraita in which the same measures of depreciation are enumerated, as in that baraita those measures are introduced with the question: How much must the sela coin be eroded so that its use in a transaction at its original value will constitute exploitation? That is diametrically opposed to the Mishnah.