[kergonath]

Indeed. Some mints even stopped putting a face value on some coins, like the Royal Mint’s Britannias.

Union Latine coins from the 19th century (mostly Swiss, Belgian, and French francs) and some British sovereigns are quite easy to get at metal value (edit: I mention these because they are somewhat old; there are plenty of 20th-century coins in the same situation). They are convenient because everyone (interested) knows how much they weight and therefore how much they are worth, give or take some Greek shenanigans.