Toothpaste cleans coins primarily through mechanical abrasion, using mild abrasives (like silica or calcium carbonate) to scrub away surface dirt, grime, and tarnish, while sometimes utilizing foaming agents to lift debris. It works best on common copper, nickel, or brass coins, acting as a polish to restore shine.
In case these coins don't have any extra value or aren't rare (you should check that first), you can clean them by washing them with an old toothbrush and dish soap, and adding toothpaste to the mix for an extra shine. Rinse well and dry with a cloth.
Soak your coins in warm soapy water** -- Add a squirt of mild dishwashing detergent like Persil Washing Up Liquid to a plastic container filled with warm tap water. Rub each coin inside this soapy bath to work off any dirt or grit. Don't put all your coins in here at once.
Toothpaste will remove tarnish, but here's the catch: It's more abrasive than silver polish, so you should use it only in a pinch and only on a small area.
Methods that work for silver jewellery can also clean copper – such as toothpaste and an old toothbrush. This method can take a while if cleaning pots and pans, but it's a reliable choice. Brush the toothpaste all over the copper cup and use the toothbrush to reach into any ridges.
Toothpaste contains abrasive particles that can polish off tarnish. These same particles can scratch silver up as well. In particular, you should avoid using toothpaste on sterling silver, highly-polished silver, or anything that is silver-plated. These items are very soft and can be easily damaged by the toothpaste.
One of the fastest and easiest ways to ruin a rare a coin is by sticking it in silver dip cleaner or rubbing it with something abrasive, like silver polish. For that reason, most coin collectors will advise you not to clean your collectable coins.
The coin is dipped into a dilute acid solution that removes the oxidation from the coin along with a small amount of metal. Overdipped coins result in loss of luster which lowers the coin's grade and appeal. According to author Thomas E. Hudgeons Jr., this is the safest way commonly found coins are cleaned.
The oil-base makes WD-40 reasonably effective at removing it without a lot of work. There is of course some sacrifice when this stuff is removed but fortunately the metal underneath is in pretty good condition and the coin, in hand, is much more presentable.
Many toothpastes contain mild abrasives, such as baking soda or silica, that can help to gently remove tarnish and restore the silver's shine. However, it's important to choose a toothpaste that does not contain any harsh chemicals or bleaching agents, as these can damage the silver.
The best home remedy for cleaning silver often involves baking soda and aluminum foil, creating a chemical reaction that lifts tarnish when combined with boiling water, or a simple paste with water for lighter tarnish; alternatively, a vinegar and baking soda soak or even ketchup can work, but always rinse well and dry with a soft cloth, avoiding harsh scrubbing or chemicals on delicate pieces.
Some stores and banks will take coins at face value if they're not too badly damaged, but it's totally at their discretion. Banks will then forward them to the Federal Reserve for deposit and replacement. If they're in really bad shape, you can send them to the U.S. Mint.
One of the most common ways of using baking soda to clean silver coins is to mix it with just enough water to turn the white, powdery substance into a stiff paste that can be rubbed into the surface of the coin by hand or finger.
