This evening I took some time to remove the sulfide covering the 1892-S quarter I found last week. I used a method I have tried over the years on heavily tarnished silver coins, and it has worked quite well.
Here is the quarter before and after removing the sulfide.
I just couldn't stand seeing the coin's beauty being hidden by the ugly tarnish.
Finally, a coin I can admire. Nothing more to do but store it.
Here is the the method I used:
Needed: Baking soda, distilled water, aluminum foil, and a glass dish.
Boil the water. Line the inside of the dish with the aluminum foil, shiny side up, and lay the coin on it. Add two tablespoons of baking soda to one quart of boiled water.
Mix in well. Now slowly pour the water into the dish, making sure the coin is fully submerged. Allow the coin to soak for 10 minutes. Remove the coin and under running water use the softest toothbrush you can find to lightly brush the coin. Avoid rubbing the coin with your fingers. Much of the sulfide will come off, but there may be some remnant depending on how heavily the coin is tarnished.
The above procedure may have to be repeated several times to fully remove the heavy sulfide from the coin. Wash the cleaned coin with distilled water and pat dry with a cotton towel. Avoid any rubbing motion!
Again, it might take several tries on a heavily tarnished coin, but the method does work well. It does not make the coin 'shiny' allowing it to retain its 'aged' look.
HH!