CoinWeek Sponsor and The Coin Course creator Jerry Shaffer teamed up with CoinWeek to produce this great step-by-step demonstration of what happens when you dip and clean vintage silver or gold coins.

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To the seasoned collector, few things are as heartbreaking as a rare coin that has been cleaned or otherwise altered in a well-intentioned attempt to make the coin look “better”.

Yet this happens all the time – frequently when a collector dies and leaves their prized collection to their non-collecting heirs. All too often in such cases, the assumption is that these “dirty old coins” would sell for more money if they got rid of all the schmutz and the coins looked shiny like the day they were struck.

Unfortunately, this is far from true, and all our well-meaning heir has managed to do is dramatically reduce any NUMISMATIC value the coin once had.

We all know the stories.

The primary reason for this destruction of a coin’s value in the eyes of collectors is due to the loss of the piece’s original surfaces.

The look of an “original surface” is hard to fake; it is created on the surface of the metal of the coin by the very act of the hard metal dies striking the blank planchet with an immense amount of pressure at a high rate of speed. The blow (sometimes repeated blows)–along with the imparting of the coin’s design–causes the metal to behave like a liquid, sending distinctive ripples across the field away from the center. When you slowly rotate a coin with original surfaces/”mint luster” back and forth at an angle, you can see a telltale cartwheel pattern that resembles spokes in a wheel appear to move around the coin.

And while dirt and tarnish can get in the way of this, there is usually enough of this luster visible that a collector knows a coin is original.

For the same reason, when this luster has been hamfistedly eradicated (such as through the use of chemicals), no matter how “shiny” and “new” a coin looks it just doesn’t “feel” right. Therefore, coins with original surfaces are more desirable to collectors and more in demand, commanding greater prices than cleaned and doctored specimens.

Don’t clean your coins.

