Question Regarding "Improperly Cleaned" Label On Coins

The general rule is "don't ever do it". Never ever clean a coin! Of course, it gets complicated. It's common, for instance, for encrusted ancient coins to be cleaned (soaking in olive oil is a popular method). I don't recommend that method for modern coins, and I don't know enough about ancients to be more specific.

Sometimes coins have grease, glue, crud or other foreign matter on them. This can be removed with a rinse in acetone (pure acetone - nail polish remover WILL NOT DO). Acetone will not harm the metal or patina, but be careful not to scratch the coin while handling. Acetone has the advantage of evaporating quickly and completely, so don't attempt to rinse the coin in water afterwards. Use the search function to find out how to do this safely - there are many threads on the subject.

Some people will recommend trying to conserve coins with verdigris or corrosion. There are differing opinions on this, and it requires special techniques. It's definitely an "advanced" subject.

Coins should really never never ever be scrubbed, rubbed or buffed. You should never ever try to remove tarnish or patina or discoloration. Don't use baking soda. Don't use acids. Don't use abrasives. Don't use soap.

Remember, you can always take more action later, but you can't ever undo a cleaning any more than you can unring a bell. It's almost always better to err on the side of doing less.

There are differences between cleaning (bad) and conservation (good). These differences can seem insignificant and I do not believe there are simple rules to distinguish the two.

Education and experience are the only ways to know right from wrong when it comes to this subject. There have been many posts over the years, too many for me to link them all. I recommend doing a search for the two terms, cleaning and conservation (both together and apart) and start reading.

Everyone, feel free to post here as well; it will only add to the educational arsenal of this site.

Thanks for the good info.

This leads me to my next question -- why don't they just label coins cleaned instead of improperly cleaned? It seems there no real way to properly clean a coin (other than wiping it off.)

Thanks for the info!

Ian

I think it implies that undetectable cleaning is okay, which is not difficult to argue. If I cannot tell a coin was cleaned, does it really matter to me?

Actually wiping a coin is the most frequently seen way to improperly clean a coin. When you wipe a coin it leaves scratches on the surface that can clearly be seen but if you dip a coin in something that doesn't remove metal or bother the surface you most likely will not be able to tell. You should never rub a coin with anything

IIRC, the sniffer is only used on their premium service.

That would make more sense, I figured running every coin through a machine would be time consuming... but I wasn't about to argue with the dealer who told me.