A Complete Guide To Cleaning and Preservation of Coins, page 9
MECHANICAL CLEANING OF COINS: Using a Toothpick
(...CONTINUED from previous page)
Most of the Dirt is Gone, Natural Patina Preserved
Now you need to clean the coin with a toothbrush and toothpaste under the running water. The next step is to examine the coin under a magnifying glass and look for any dirt remaining inside the lettering or in other small features of the coin's design.
Dirt Residue Inside Letters on Coin Design
Additional application of a toothpick and then brushing would get the coin cleaning job done.
If you would like to recommend this article on "mechanical cleaning with a toothpick" to everyone, please click the button: