An apparatus is provided wherein, in a static condition a lower phase liquid is covered by an upper phase liquid which is non-miscible with the lower phase liquid. In operation, the upper phase liquid is removed from a selected area of the lower phase liquid by raising the upper phase liquid to pass over a weir into a second chamber. Simultaneously a portion of the lower phase liquid is circulated over a second weir and caused to pass through a portion of the upper phase liquid to provide a scrubbing or cleansing action. When operation ceases the liquids automatically return to the static condition levels wherein the lower phase liquid is completely covered by the upper phase liquid. During operation articles or materials may be caused to enter and exit the lower phase liquid in the selected area, for treatment therein without contacting the upper phase liquid. The apparatus is useful in cleaning, degreasing, plating, pre-plating treatments and the like.