Tanacat, I went over to Amazon.com again and looked at that Renaissiance Wax that the Royal Museums use in the UK and it does say that it halts further corrosion and rusting. Alot of their items are Relics like Swords and other items but it does say it will work on Copper. Look at the area that says reviews by people who have used the product. I would think if it's good enough for a Museum then that's proof enough for me to try it on some of my Coppers that have lost some detail. As you wax the coin, it also will remove some of the extra oxidation and clean it slightly.
Remembr though, don't ever use any cleaning product or wax on a coin you plan on having authenticated or graded. That's if you can find one that grades regular ":grin:UG coins. Do anyone know of a grading company that grades dug coins ?
*** Notice : I only mentioned Copper coins. I don't believe in cleaning Silver or Gold coins unless it's been done Professionally like the Shipwreck Coins .