Greetings, I have recently acquired a coin collection and I am quite unfamiliar with many of the abbreviated codes written upon each cardboard holder. I am starting to do research with the pennies as they seem like the logical place to start. Is there a place in this website that can help me understand what some of these abbreviations would mean? Such as RPM013, D/D, East, IDO004 and Eye Lid etc. Any help would be greatly appreciated.