Commentary for Kiddushin 111:5

אמר מר אם לקח יאכל כנגדן ואמאי יחזרו דמיו למקומם כי התם

it in Jerusalem.<span class="x" onmousemove="('comment',' Hence there is no question of penalizing anyone (Rashi) . Tosaf.: But the vendor thinks that since when one usually buys an animal with second-tithe money, the animal becomes sanctified and the money hullin, so is it now, the stipulation being unable to abrogate normal practice.');">⁹</span> R'Jeremiah demurred: But what of unclean cattle, slaves, and real estate, in regard to which a man knows that second-tithe money is not secularised by [the purchase of] them; yet we learnt: Unclean cattle, slaves, and land may not be bought with second-tithe money, even in Jerusalem; and if he does purchase [them], he must eat to the value thereof?<span class="x" onmousemove="('comment',' I.e., he must take fresh money and declare, 'Wherever the first money is, let it be redeemed by this,' and expend it in Jerusalem. But we do not assume that the vendor himself will take the money thither.');">¹⁰</span>

Daf Shevui to Kiddushin