How to Clean Coins: The Best Ways to.. Web  Clean copper coins in a vinegar and salt solution. Dissolve 1 tsp (7 g) of table salt in a bowl with 1⁄4 cup (59 ml) of white distilled vinegar. Drop your coins into the mixture and let.

Web  If your coins are still dirty, you can fill the plastic container with a 1-inch layer of warm water. Next, add a squirt of dishwashing liquid and agitate the water to create bubbles..