Received pesos from 1991

My Uncle left in a safety deposit box money from a trip to Mexico he took in August 1991.

I went to go exchange the money at a US bank and they said the bills are too old to exchange. What can I do?

My Uncle left in a safety deposit box money from a trip to Mexico he took in August 1991.

I went to go exchange the money at a US bank and they said the bills are too old to exchange. What can I do?