pass a sponge over the slate

== English == === Alternative forms === === Etymology === In reference to a wet sponge being used to wipe a writing slate clean. === Verb === pass a sponge over the slate (third-person singular simple present passes a sponge over the slate, present participle passing a sponge over the slate, simple past and past participle passed a sponge over the slate) (obsolete) Synonym of wipe the slate clean. [19th century] Synonym: draw a sponge over the slate