Everything else you see is environmental damage to the coin's surface - after it's been in circulation. Not an error coin, sorry.
Ok,so how can I differentiate this nickel...which,I guess is a stain,idk,from say...the quarter i posted before(below) which seems to have the same characteristics at first glance What is the giveaway on the nickel to determine that it isnt lamination @Fred Weinberg
The metal on the nickel appears uninterrupted where as on the quarter it appears almost like a fissure. Also, the edges of the stain on the nickel are that of a pooled liquid. This guy was likely in someone's cup holder for a long time. I've found with these types of coins if I angle it around under a light source it becomes clear whether it is just the surface that is effected (like with stains or grime) or the planchet or cladding. It also helps reveal moved metal which means PMD too. If you look at stains like these straight on they can be compelling but once you move it around under a light you can tell that it is flat.
