Kikar is reporting on an interesting psak from Rav Moshe Shternbuch, Raavad of the Eida Hachareidis and Rosh Yeshiva. 

Rav Shternbuch, in a shiur in his yeshiva,, referred to a case that had  come up in beis din. He was presiding over a case and they decided that the person being sued had to pay a large amount of money to the other litigant. He continued to claim he was being set up, and lied about and this is theft, etc. but the dayanim held strong and said that according to halacha he has to pay, and should he refuse, they will issue a "ksav siruv" against him for ignoring the psak of the beis din.

Rav Shternbuch says the next day this fellow shows up in the beis din with several sacks full of 5 agura coins, which were still in the currency back then. He handed it over saying he was paying up in full, and that he had been told by a rav that because the 5 agura coins are valid currency, this is a valid payment.

 Rav Shternbuch called the bank to confirm the status of these coins and was told that by law it is valid currency and can be used for payment.

However, paying in this fashion would cause a lot of trouble and expense for the other person, as one cannot use so many  of these coins in one place or take it to any bank to convert to other bills. One had to take it to the Bank of Israel, and even then the BOI would not convert it immediately but would do so after a week.

 The final psak after deliberating the various perspectives, each a valid opinion in halacha, was that really this cannot be used as payment in every store as they wont accept it so it is not really considered "over lasocher", valid currency, but there are some scenarios where it would be accepted.

And if the 5 agura coins were questionable and possibly not good enough, could he go back home and prepare sacks of 10 agura coins, which were perhaps more usable and are even today still part of the currency? would it matter if he used 1 shekel coins? is the problem because institutions cant handle so many coins or was the problem specifically with the 5 agura coin?

 Back in yeshiva (high school) it was a lot of fun when one of the guys would pay a fine (for coming late to davening too often, or late for curfew or whatever) in pennies or nickels.