Electrolysis done right will give you better results on copper coins than any other method without the damage caused by chemical or mechanical means. Done wrong it can remove detail or pit your coin. Do a web search using keywords electrolysis and coin. You will find several sets of instructions. An old 9 volt AC/DC adapter from some no longer used electronic equipment makes a great power source. It is hard to tell someone how long to put current to a coin because there are so many variables such as voltage and amperage used, condition of the coin, temperature of the water, type and amount of electrolyte used, distance from coin to electrode, etc. So practice first with nonvaluable copper coins(not zinc). A mild acid such as vinegar, lemon juice, or weak muriatic acid is a lot easier and OK for low value coins, but you can always tell the coin was artificially cleaned. Electrolysis is a lot more trouble, but done correctly, a high value coin can come clean without looking cleaned. Don't try to get the coin completely clean with electrolysis. The process moves the outer shell of electrons from your coin into the electrolyte solution and in the process turns the caked on gunk into mud that can be mostly removed with a very soft toothbrush and plain water. HB
