You have a lot of old coins, but they are all covered in rust. To clean them, you can use specific detergents, but you would get good results using acidic solutions such as vinegar, lemon juice or soft drinks. Think carefully before starting: if you plan to sell them, removing the rust and corrosion could significantly decrease their value!
Steps
Method 1 of 3: Know which Coins to Clean
Step 1. Don't trade coins if you plan to sell them or if they have potential value
Any attempt at cleaning greatly lowers its value; if you hope to be able to sell them for a price close to the collector's price, avoid removing corrosion (such as rust), encrustations (such as dirt) and any other substance that covers them. If the ones you want to clean are part of a numismatic collection (the scientific study of coins), do not proceed with the cleaning, otherwise you will considerably affect their value; entrusts the work to experts in the field.
Step 2. Handle them with care
Any potentially valuable coin should not be touched with bare hands; put on gloves and place each piece in plastic bags. Have your coins evaluated by a professional before proceeding. The same goes for any antiques: do not clean, paint or polish anything that may be of value before having it submitted for an appraisal.
Step 3. Do not clean coins made mostly of copper (such as cents) together with those made of other metals
If copper is left to soak in the same cleaning solution, it can cause the surface of other materials to discolour. If you take euros into account, this means cleaning the 1, 2 and 5 cent pieces separately from the 10, 20, 50 cent pieces and the 1 or 2 euro pieces.
Do not soak copper coins with steel ones; copper could react with the cleaning solution and release particles that bind to the steel, ruining the finish
Method 2 of 3: Use Coin Cleaning Products
Step 1. Use a metal polish soap
To remove rust and other similar corrosion from most coins, you can use a car polish soap. You will be surprised of its effectiveness against the rust stains present on the surface of the coins; it is perfect for silver pieces and some silversmiths use it to polish jewelry made with this precious metal. The sponges or wadding for silver are useful because the cotton or wool fibers allow you to clean the irregular surfaces of the coins; household products for polishing metals should also be fine.
Step 2. Look for metal cleaners at auto parts stores
Take a look at the supermarket shelves dedicated to cars to find polishes and metal cleaners that can also be used for coins. You can use products for silver, copper or other types of metals - each substance is more effective for the specific material it is formulated for.
Step 3. Use an ultrasonic jewelry bath
Remember to proceed only if the coins are not collectible, do not clean the ones you keep in order to increase their monetary value. Follow all manufacturer's instructions and recommendations when using an ultrasonic cleaning device.
Method 3 of 3: Clean Coins with Household Products
Step 1. Wash the coins with cold running water
Keep them by the edges, because if you touch the surface directly you can leave small scratches; if you want to protect the faces of the coins, don't rub them.
Step 2. Run the water for about a minute
The higher its pressure, the better; do not use high pressure devices which could even pierce the coin.
Step 3. Brush the coin lightly
If any traces of dirt remain, gently scrub the surface with a soft-bristled toothbrush and dish soap; to soften the bristles even more, wet the toothbrush with hot water. Rinse the coin and the toothbrush often to avoid scratching the metal with dirt residues; do not exert too much pressure and focus only on the dirty areas.
There are several types of toothbrushes categorized according to the stiffness of the bristles - you need to buy one with soft or extra-soft bristles. If you use rigid ones, you risk damaging the coin
Step 4. Locally clean the encrusted dirt
Some stains may not disappear after soaking and brushing, especially on old coins. To remove them, use a small pointed tool such as a toothpick or a precision screwdriver. Gently pry to remove encrustations, taking care not to scratch the surface; you can do an even more precise job if you use a good light source and a microscope or magnifying glass.
Step 5. Pour some vinegar on the coin
Wait about ten minutes and then scrub with a toothbrush; in this way, you give the metal a shiny look. You can use any acidic substance like lemon juice and apple cider vinegar; even soft drinks are believed to be able to remove rust from old coins.
If you wish, add salt to the vinegar (or lemon juice or soda); the combination of acid and chlorine makes the cleaning solution even stronger
Step 6. Rinse the metal once more
After washing it, rinse it thoroughly with warm running water; if you are satisfied with the result, dry the coin. Do not leave the acid substance in contact with the material, otherwise it continues to consume it, producing an unsightly green patina of copper salts.
Step 7. Dry the coin
Dab it with a soft, lint-free cloth and then place it on the fabric itself to finish the drying process. Don't rub it.
Warnings
- Do not leave the coin in the vinegar for too long and do not rub it excessively, otherwise the details begin to fade!
- If you don't want them to wear out and lose much of their value, don't clean old precious coins, especially with acidic or abrasive substances.
