The term slush began as a sailors’ reference to the grease from the cook’s galley, which was used to lubricate the ships masts.
When the voyage was over, the surplus grease was sold, and the money was put into a “slush fund” to be shared by the enlisted men.
By 1839, when a ship returned to port, any surplus supplies or battle-damaged equipment was also sold and the money added to the profits from the grease in the slush fund.
These days, a “slush fund” refers to a stash of surplus money.
