Lye
Archimandrite Nikifor’s Biblical Encyclopedia
(Jer. 2:22; Mal. 3:2)—a cleansing solution made from caustic salts, sometimes combined with oil. Through Isaiah the Lord says, “I will turn my hand against you and will smelt away your dross as with lye, and remove all your alloy” (Isa. 1:25). Jeremiah declares that even if Jerusalem washed with lye and used much soap, her guilt would remain marked before the Lord (Jer. 2:22).