Cleaning

A dull penny presses into a dull souvenir. Over twenty years collectors have tested everything from ketchup to denture tablets, and most of it works to some degree. These are the methods that hold up, in rough order of how often they get recommended.

The soak: vinegar and salt

Dissolve a tablespoon of salt in half a cup of white vinegar, drop the pennies in a single layer, and watch the tarnish lift. Five to ten minutes is plenty. Scrub stubborn spots with an old toothbrush, rinse well, and dry.

The coins come out clean but pink and matte. Mix baking soda with a little water into a paste, rub it over each penny with a thumb, rinse again, and the shine comes back.

Lemon juice and salt, ketchup, cola, apple cider vinegar, and hot sauce all work on the same chemistry. Lemon juice packets from a restaurant are the travel version. Two warnings from experience: soak coins separately or the grime moves from one to the next, and never leave them overnight. A penny left in acid too long turns black, though a pencil eraser will usually rescue it.

The eraser

No chemicals, no smell, safe for children. Rub the penny with a plain pencil eraser until the gunk comes off. For more than a handful, fit a short pencil in a variable-speed drill, or buy an electric eraser from an art supply shop. Slow, but the result is a clean coin with none of the pink cast a soak leaves.

Metal polish

For the brightest finish, use a copper or brass polish. Wright's Brass Polish is the collector favorite: water-soluble, fast, and tidy. Brasso and Nevr-Dull work too but take longer to clean up. Rub on, let it sit a minute, buff off with a paper towel. When the towel turns black the polish is doing its job.

Wear gloves with anything stronger such as Tarn-X, and wipe every trace of polish off the coin before it goes anywhere near a machine.

Cleaning by the hundred

Serious collectors carry fifty pennies and three rolls of quarters. For that volume, a rock tumbler with plain vinegar, run for three or four hours, does the work unattended. The toothbrush head from an electric toothbrush chucked into a drill, with a little Bar Keepers Friend, is the hand-held version.

Bench grinders and wire wheels do strip tarnish in seconds, and they also strip metal, heat the coin, and will fling it across the room if the pliers slip. Not worth it.

Sticky residue

Tape glue and candy do not always press out. Wash in hot soapy water first, then a dab of Goo Gone in the crevices, then one of the methods above.

Pennies that are already pressed

Gentle only. Warm soapy water and a soft toothbrush handle most grime. For black spots, a pencil eraser. Old zinc pennies that have gone green or black can be brought back with a very light pass of a soap-filled steel wool pad, then sealed so the air cannot get at them again. No acid, ever, on pressed zinc.

Keeping the shine

Air causes tarnish, so the finished penny should be bone dry and go into a tight sleeve or a sealed container. For a permanent fix, see the clear-coat note on the Storage page. Whatever the method, try it on a spare penny first.