The hobo nickel is a sculptural art form involving the creative modification of small-denomination coins, essentially resulting in miniature bas reliefs. The nickel, because of its size, thickness, and relative softness, was a favored coin for this purpose. However, the term "hobo nickel" is generic, and carvings have been made from many different denominations.

Due to its low cost and portability, this medium was particularly popular among hobos, hence the name. The altering of coins dates to the 18th century or earlier. Beginning in the 1850s, the most common form of coin alteration was the "potty coin," engraved on Seated Liberty coins (half dime through trade dollar). This time period was also the heyday of the love token, which was made by machine-smoothing a coin (usually silver) on one or both sides, then engraving it with initials, monograms, names, scenes, etc., often with an ornate border.