Put down the scrubber. It's never bath time for coins. No matter how dirty, worn or tarnished they are, the filth is part of their charm (aka value). Over time, coins go through a natural process called '
Cleaning or polishing rare coins devalues them. So, if you're planning on selling them, get an appraisal before attempting to clean your coins.
Before cleaning old coins, consider that appraisers and coin experts suggest not cleaning collectible coins yourself because the coins may lose their value. Using chemical cleaners or scrubbing the coins can leave behind scratches and marks, easily seen by a skilled coin appraiser.
Don't clean your coins! Not only does this cut their value by as much as half (or possibly even more), but it will be an immediate deal-breaker for many dealers who would've otherwise wanted to buy your coins if only they were left in their original condition.
Since oil and dirt cannot be removed without cleaning, a small touch can cut a coin's value in half or even more because, again, numismatists would rather have an oxidized but untouched coin than a shiny but damaged one. The bottom line for anyone looking to sell coins from a coin collection: don't clean your coins.
Distilled water is recommended as tap water contains chlorine. The coin is dipped into olive oil which according to Hudgeons, works best for common copper or bronze coins.
Judge the age and consistency of the color, its depth and evenness. The underlying luster should be undisturbed and in a perfect cartwheel pattern, this being especially visible about the obverse stars. Look for hairlines or other imperfections that may indicate the coin was cleaned at some time in its past.
CoinFacts (PCGS mobile app) Many coin collectors say the first place to start for any coin collector or enthusiast is with PCGS — offering a variety of different coin-collecting apps for both iOS and Android. PCGS claims they're the industry standard for grading and valuing coins.
Make sure your coins have been cleared of all dirt, debris and other objects prior to visiting the kiosk to ensure a successful transaction. Items like food, screws, dirty or sticky coins and other objects will jam the machine.
It was a common practice for coin collectors to "clean" their coins to keep them in mint condition. As time progressed, more and more metal was removed from the surface of the coin and thus destroying some of the finer details on the coin.
Even though it's counterintuitive, you should never clean a coin, as it can significantly reduce its value. Even coins that have substantial dirt, tarnishing, or toning should be kept in their original condition.
Coins that are obviously dirty can be run under water (with a very mild detergent) and left to air dry. A short soak in olive oil may remove unwanted gunge. For cleaning corroded coins the damage is already done, they will forever show pitting into the coin surface. This is as far as anyone should go with cleaning.
You can sell your coins by taking them to a local coin store, searching for a dealer online through reputable sources like The American Numismatic Association, taking them to a coin show, or submitting them to be sold at an auction.
Use Hand Sanitizer
This buildup causes the metal to tarnish and can increase the amount of wear and corrosion on the face of the coin. The more the face of the coin is handled, the more subdued the features will become. Hand sanitizer will remove the bulk of those troublesome oils.
Easily the best method to clean clad and other common finds. Place your coins into a rock tumbler with a small amount of fish gravel from a pet store. Add some vinegar, salt and lemon juice - and get to tumbling. This only takes about 30-60 minutes until you see a huge difference.
If the coin has a flat luster but yet is dated it has probably been dipped, most coins will have a frosty, smooth or glossy lustre if they are untouched and you can easily see the difference. Wizzed or tooled coins can be detected by small abrasive marks on the surface of the coins, often the finish will be mirrored.