Store rare coins in Mylar plastic coin flips, or ask a coin dealer for alternatives. PVC coin flips can damage your coins.
Tap water contains chlorine that can lead to discoloration. Tarnish (a thin layer of grey, black, or iridescence also called “toning”) is not the same as dirt. [2] X Research source If the coin is rare, toning may even be a desirable feature that raises the coin’s value.
Cheap, non-virgin olive oil works better than virgin or extra-virgin, since it is more acidic. [8] X Research source If the coins are not valuable as collector’s items, you can skip to the harsh cleaning methods instead to save time. If the coins are rare or unidentified and you don’t want to wait months, take them to a coin collector for advice.
You can run the machine without the cup, but dirt or objects on the base of the pan will interfere with the pan’s vibration and shorten the machine’s lifespan.
An even gold, grey, or iridescent tarnish (toning) is desirable and increases the coin’s value. [11] X Research source A black or blotchy tarnish is not ideal, but harsh cleaning can still lower the value. Continue very carefully or take it to a professional.
Pointy plastic utensils are slower, but less likely to scratch the coin.
Put a coin-sized dollop of polish on a soft cloth. Fold the cloth in half to transfer the polish to two sides. Place the coin between the fold of cloth. Rub together briefly. Wipe off the coin on a clean part of the cloth.
Don’t leave the coins in the vinegar solution for longer than 2-3 minutes! Otherwise, the mixture may erode their surface features. [14] X Research source Make a fresh mixture for each batch of coins. You can also immerse the coins in an alkaline solution to neutralize the acidity of the vinegar[15] X Research source . Make a simple alkaline solution by dissolving 1. 5 teaspoons (7. 2 grams) of baking soda in a glass of water. Mixing coins of different compositions may cause them to stain each other.
Warning: ammonia liquid and fumes are corrosive. Wear neoprene gloves and work in a ventilated area. [17] X Trustworthy Source US Occupational Safety and Health Administration U. S. government agency responsible for setting and enforcing workplace safety standards Go to source Some hard buildups are the result of a different chemical reaction, which may require other treatments. Consult a coin dealer first if the coin might be valuable.
Soak the coin in a 50/50 mix of distilled water and lemon juice for one hour. [18] X Research source Soak the coin in 1 tsp (5 mL) lemon juice mixed into 1. 5 cups (360 mL) olive oil. Warm this in a heat safe container inside a water bath, but keep it below boiling. [19] X Research source “Dipping” treatments can return a coin to a frosty white silver appearance, which some collectors value. However, this is an extremely risky procedure that can cause blemishes to appear. Hiring a professional is strongly recommended, but you can buy a dipping solution to use at home. [20] X Research source
