Has anyone tried using the new mini Reeces Pieces containers? They are oval, and I am hoping that they might be just the right size for the pressed pennies.
Also, you can use vinegar and salt to clean the pennies (1/4 cup white vinegar per tsp. of salt). Just put the pennies in for 5 minutes, maybe stirring occasionally. They come out shiny. However, be sure to rinse them in water immediately or they will turn green later. Also, the oxygen in the air will almost immediately start turning the copper brown again; a ziplock bag can help.
My kids and I turned this into a science lesson. We used the vinegar and salt to remove the copper oxide from the pennies, then removed the pennies and rinsed them in water. You can then put nails and screws into the vinegar solution, and they will turn a copper color (or darker) as the copper is deposited on them.
You can do a google search on cleaning pennies and science expiriment.