The zakah on foreign currency checks after the loss of the purchase invoice

Question:
He says: Honorable Shaykh, may Allah grant you success. The questioner says: Fourteen years ago, I paid local currency to purchase foreign currency checks. I spent some of them and kept the rest, and I did not pay their zakah for all the past years. Three years ago, the purchase invoice for those checks was lost from me, so they became like invalid currency. I was no longer able to sell them, and this year I was able to exchange them for another currency. He says: How do I pay their zakah for the past years after their type and value have changed? And is there zakah due on me for the years in which the purchase invoice was lost?

Answer:
These are money, and the zakah on them is based on their value. These are money; if they reach the nisab (minimum threshold for zakah), you pay zakah on them every year, and you do not look at their value, because they are themselves zakatable wealth. It is trade goods and commodities whose value is looked at. These are not trade goods; these are money. So they are subject to the zakah of money, the zakah of currency, at one-quarter of a tenth every year. Yes.