Q&A for How to Clean Copper Coins in Seconds

Since all alcohol is neutral (having neither acidic or alkaline charges) it will only remove ceraint oil base soils. The advantage is it will not cause any decrease in numismatic value, but there are better options for cleaning materials.

Ultrasonic cleaners work by microcavitation. Or in layman's terms, by generating microscopic bubbles between a hard surface and a softer material, and allowing them to catastrophically collapse. This process only works in fluid. So at the very least you need distilled water as a working medium. As for what is best to add and enhance the cleaning action, I'm not sure. Caution: blood plasma counts as a fluid. So if you leave your hand in the ultrasonic cleaner long enough, it will "clean" the flesh from your bones. This is usually only a concern for industrial levels of exposure.

HCI works, but you get an orange look to the copper and still need to use your elbow grease to clean it.

Yes, you can.

You can clean them by putting them in vinegar for a minute and then taking them out.

Dip them in ammonia, flip them over after five seconds, rinse well with water, and pat dry with a soft cloth.

Yes. The salt acts as an abrasive and will instantly decrease the value of the coin.