Muslim nations looking to fight back against future sanctions are exploring an age-old approach — using gold dinar and bartering.

Leaders from Qatar, Iran, Malaysia and Turkey met during the Islamic summit in Kuala Lumpur to discuss the matter this week.

“With the world witnessing nations making unilateral decisions to impose such punitive measures, Malaysia and other nations must always bear in mind that it can be imposed on any of us,” Malaysia’s 94-year-old Prime Minister Mahathir Mohamad told Reuters.

“I have suggested that we re-visit the idea of trading using the gold dinar and barter trade among us.”

“We are seriously looking into this,” he added.

The idea is no joke for many of the nations involved. In the Middle East, Qatar has been increasingly isolated from their Arab neighbors that are allied with the United States. Iran has faced decades of sanctions and international isolation from the United States.