It is like washing bricks, which the more you scour them, the more muddy they become; meaning bricks made of clay, and not burnt, but dried in the sun; such as were used in the East, and probably are so now, or «Laver la tête d'un âne», by which the French designate such unavailing attempts. The proverb may also be applied to persons, endeavouring by fictitions ornaments to make any thing appear more beautiful and valuable than it is, or by rhetorical flourishes to give a false colour to any action.