Gold

Gold (金 kin, lit. "gold") acts as a system of money/currency in general use for the people of the Spirit Realm introduced in the Japanese animated film Spirited Away. It is considered highly valuable by Yubaba and the other Bathhouse workers, but ultimately ends up bringing misery to those who show their greed for it.

Method of Use
Spirits seem to earn and spend gold as Humans would earn and spend money in the Human World. Gold, like money, can also be tipped to workers from generous spirits and used to exchange better Bath Tokens in The Bathhouse. A Spirit's power and influence depends on the amount of gold he or she possesses, as seen when Yubaba praises Sen for serving the generous Unnamed River Spirit who tipped The Bathhouse a large amount of gold pieces upon his leave.

Zeniba had a monogram seal apparently made of gold, which Haku, under orders from Yubaba.