Eldon's lucky coin is an object that is not mentioned until Season 3.
Eldon mentions his coin for the first time in "Today I'm Getting Over You" while explaining to Skylar the nature of his pre-competitive rituals. Subsequently, after rummaging through his pockets in order to utilize it as an exemplar, Eldon discovers that he has lost it. For the entire episode, he searches for this coin and never finds it. After taking pity on him, Ella gives him her own lucky pound, which ultimately replaces his original lost coin.
Eldon loses this new lucky coin by dropping it into the water when stuck in the Everglades while attempting to make a sacrifice to the "alligator god." After an elaborate plan via James and West, he believes that they have retrieved his coin. Although, after exiting the Everglades, he realizes that it is not the right coin due to its different date.
In "Danger Zone," it is revealed that Eldon's lucky coin is taped onto the wall of the closet in Studio A. It can thus be assumed that Eldon's original lucky coin was found and kept there for safekeeping, as this is the only plausible explanation for its reappearance.
Eldon's lucky coin is a silver 1984 Canadian quarter. Its replacement coin, an English pound, is never seen in detail, although it is round and metallic.