Comment by aDyslecticCrow

I think stores will adjust their prices pretty quick if they cannot even aquire pennies to give as change. So no law should be needed.

you may need to stipulate a grace period during which stores are still obligated to take pennies, to slowly shake them out of circulation without every American needing to visit a bank for cashing in. But its also possible that isn't needed either.

In the 2nd half of the phaseout you may need a proper marketing campaign to remind people to cashe in before expiration. (common when other countries update their physical currency). But that is probably the job of a different sitting president anyway so whatever.

Heck, is this actual something that congress have say over? It wouldn't surprise me if this was actually up to the federal reserve to decide, and they seem on board.