Things You'll Need
Instructions
Put a teaspoon of salt into a glass of tap water. Use a spoon to stir it. Leave the spoon inside the water and get a 12 volt or higher adapter. There are two clips, one on the positive side and one on the negative side. In order to tell which is positive and negative, you will have to perform a test.
Plug in the adapter and place one of the clips into the salt water attached to the coin. If it doesn't sizzle, then take that one out and switch it out for the other clip. This one should sizzle, and it will be the negative clip. Attach the other clip to the spoon inside the salt water.
Watch the water become dirty within a few minutes. The dirt is from the dirty coin. The water will become cloudy, and the longer the electrolytes continue to clean the coin, the dirtier the water will become.
Stop after five minutes. Check the coin to see if it still needs deep cleaning. Depending on how dirty the coin is, it may need a repeat of the steps, but no more than one more time. After five minutes, disconnect the coin and spoon and remove them. Put the spoon into the sink and place the coin onto a towel.
Get an old toothbrush and put some baking soda onto it. Brush the coin with the toothbrush and rinse. It should appear very clean and shiny. Unplug the adapter and dump the dirty water into the sink. Place the coin on the towel to dry.