As Salamo alaikum. I have lot of old coins of 1, 2 and 5 rupees.There is a process by which I can exchange these old conins. By exchanging these old coins,I get more money than the original value.For Example,if I give an old 2 rupee coin,I get 4 rupees or even more in return.So,is the extra money which I get while exchanging halal for me or not.
Ref. No. 37 / 1051
In the name of Allah the most Gracious the most Merciful
The answer to your question is follows:
Exchanging old coins and getting more money than the original value in return is unlawful.
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband