Cleaning!

[Guest]

Anyone heard of the lemon juice and salt method? It disolves most "petina" but does not "damage" the coin in any way that i can tell! Afterwards buff lightly with baking soda mixed with water, which does not scratch, to a mint like shine. Dont understand how this affects the value of a coin if your only exposing the original surface of the coin!!?? Afterall how are you gonna see some errors that occured in 1945 or whatever if there is a buildup of "petina" that has built-up on the coin? Still Learnin!!

[Roller]

Patina does not "build up"; it is the tone that a metal takes on with age (oxidation) and handling. Once you alter a coin by removing it you can forget about the assigned value.

[coinman2009]

That's a no no, Salt and lemon juice sounds pretty corrosive to me, It's best just to let them be. The value of cleaned coin's is greatly diminished, and most people can spot them right away.

[hasfam]

There are better ways to remove dirt and crud from a coin in order to better examine it for varieties that is safe for the coin and maintains the integrity of the patina. But, even with those methods, extreme caution must be used. Try running a search on this forum for cleaning. There have been quite a few really good threads with great advice on to clean or not to clean and some practical and safe ways to do so. Good luck.
Rock

[jfines69]

Lemon juice is actually an acid (All citrus juice is)... You may not be able to see the effect but it will damage the surface... Salt causes corrosion anytime moisture is present... The baking soda and buffing causes microscopic scratches... However I do agree with you about the petina... I believe it is better to remove dirts and oils to prevent future damage to the coin than to preserve the petina... There are better ways to remove the dirt and oils!!!

[BadThad]

Lemon juice - citric acid
Salt - chloride ions

Both are highly corrosive to metals and if you use this on a coin all collector value is essentially gone.

Baking soda, sodium bicarbonate, is a weak base and is also corrosive and will cause hairlines on the surface....another horrible idea. If you value your collectible coins AT ALL, do not use these chemicals on them.

[jfines69]

If I remember correctly... The oxidation (Corrosion) starts the petina... The color comes from dirt and other contaminants such as body oils and airborn particulates... The oxidation for the most part protects the metal... The only time the oxidation causes problems is when the dirt and other contaminants are acidic or salty in nuture... Then the petina becomes harmful to the metal!!!