Penny rolling... Obverse looks decent, reverse with acid like bubbles however the flow of melt from the "O" to "N" in ONE and "N" to "T" in Cent is high and even with the letters. Acidic looking bubbles west/southwest reverse but the flow of the copper between those couple letters is pretty smooth if it's a curb side acid damage job. No clue, just wanted to share. Thanks CT Crew
Looks like it was glued to something for many years, so the glue protected some of the original surfaces while the rest of the coin toned during normal atmospheric exposure. Then it was popped off the backing, leaving some of the glue. You can try a soak in pure acetone to remove the glue, but nothing is going to fix the difference in exposure to the atmosphere except time which will make the whole thing - at best - an ugly uniform dark brown in another 80 years.