A New Coin Cleaning Project. 1803 Large Cent

Great progress. I like the coin as it is right now and look forward to photos of your additional steps.

I've very much enjoyed following your process and progress. It takes a very long time to get passable results and you did a great job.

Joe

thanks everyone!

one of the problems that this coin is presenting is that it was improperly cleaned before it was glued to whatever it was glued to. someone polished it.

polishing a coin has a permanent impact on the metal. it alters the surface. I drew up a quick diagram to help with visualizing the concept.



in the upper left you see a circle with arrows. this is to show the directional flow of metal that happens when a coin is struck. when the dies strike they smash the coin and compress it outward. over many iterations this process etches radial lines into the surface of the die. those line are called flow lines or mint bloom and are what give coins that cartwheel luster.

upper right is a section of what flow lines would look like under significant magnification. they are small ridges in the surface of the coin. they create a lot of surfaces for light to reflect from and for environmental reactions to occur on.

the lower two examples are what happens to a coin when it is polished. the tips of the ridges are removed. that creates a hard and flat surface. this uniform and hard surface is often reflective. it is smooth and difficult for reactions and patina to adhere to.

wear and polish both remove the peaks of the flow lines. wear will do it in a haphazard way and leave behind microscopic nicks and dings and dents. these nicks and dings and dents will allow patina to take hold and tone the surface. polishing will make the surface uniform. its hard for something to stick to a mirror.

this is one of the big reasons people are told not to clean coins. if you use improper techniques and arent careful you will permanently alter the surface of the coin.

I agree with @ bikergeek, this is an excellent and deceptively simple description of the impact of cleaning a coin. Very well said CarrsCoins.

sure. I can do that.

you caught me between steps. its currently sitting on my porch.



to help with the cleaning problems I mentioned in my previous post I have been doing two things. I carry it with my change until the surface patina rubs/is nicked off. then I leave it outside to recolor. pocket. outside. pocket. outside. ect. the goal here is to build a real and natural patina. it takes time, patience and attention to detail.

this is a really easy way to ruin your coins if you are not careful

pocket can scratch/damage the coin and its east to lose. outside can have runaway environmental problems so it needs to be examined frequently. when outside I examine and flip it regularly.

here is what it looks like today. it looks a touch better in hand. those pinkish high points can be brought back to brown with some time and patience.




i would like to draw your attention to the fact that there is a rim bump over the L in Liberty and a pin prick a little below and to the left of that. those flaws will make this coin easy to track across all the various iterations of dirty to clean and raw to patinated.

im probably around 3 hours at this point. I'm just counting dedicated focused time. things like playing with it while watching tv arent counted there.

Very impressive results!

Coming along nicely.

Excellent work! I developed my own copper cleaning process using ultrasonic cleaning and proprietary chemicals after 40 years of collecting high end copper. I doubt I could exceed this effort on this particular specimen. The difficulty here is to create somewhat a uniform brown color as the Cu-oxide areas removed creates surface color differences with the non-oxidized areas. John Lorenzo, Numismatist.