Abstract: A method of cleaning drilling fluid tanks is provided. The method includes washing drilling fluid within a first tank with fuel oil thereby forming a first admixture of drilling fluid and fuel oil. The method further includes reclaiming the first admixture and washing drilling fluid within a second tank with the reclaimed first admixture. The method further includes reclaiming a second admixture formed by the first admixture and the drilling fluid from the second tank. The method further includes washing drilling fluid within a third tank with the reclaimed second admixture.