There are many ways to make pennies sparkling clean. One option is to first lay out a piece of aluminum foil in a tray. Next fill up the tray with some warm water and mix it with salt. Last place the pennies on top of the foil, wait for a couple of minutes, and you'll have sparkling clean pennies.
Pour the salt and vinegar into the bowl.Stir until the salt dissolves.Dip a penny halfway into the liquid and hold it there for 10-20 seconds.Remove the penny from the liquid.Dump the rest of the pennies into the liquid.The cleaning action will be visible for several seconds. Leave the pennies in liquid for 5 minutes.
One unusual way to clean pennies is to put them in a bowl of ketchup for a few minutes and then rinse them. You can also try to soak them in vinegar and then rinse them. Bar Keeper's Friend should also work. The same approach can be used on copper pots and pans.
Don't try this on a collectible older penny! Open a packet of Taco Bell hot sauce and smear it on the penny. After a few minutes, rinse and wipe the coin clean to reveal the shine. This particular brand of hot sauce works the best for cleaning dirty pennies. I think they use more acidic ingredients in the sauce.
There are two different solutions you can use. First, you can use vinegar to shine up those cents. Or, you can use a solution of salt and lemon juice and shake them in a plastic covered cup.