hags wrote:68Camaro wrote:Incorrect - it doesn't "polish" anything. It simply converts silver sulfide to hydrogen sulfide gas and loose silver which wipes off. It leaves the fundamental silver metal untouched, doesn't change the underlying surface at all.
If you "wipe off" a coin that's been in baking soda and water then you have polished the coin...1 wipe or multiple, it's polished and has been cleaned...
The underlying surface is void of mint luster and aged patina..how can you say it doesn't change?....
hags
Polishing is an abrasive process, while cleaning can simply refer to rinsing a coin in water or acetone, both of which are accepted practices. Harsh cleaning, on the other hand, is dipping the coin in an acid solution which dissolves a portion of the metal...and even that method of cleaning is acceptable by PCGS as long as it isn't overdone or improperly used on a circulated coin.
Electrolytic cleaning as described by 68Camaro is an intermediate method between rinsing and dipping, which is used by professional restoration services. With that being said, however, it doesn't work very well on heavily circulated coins because the worn (polished) areas come out looking too shiny.