Abstract: A floor cleaner having a rigid vacuum-retaining outer case, which is adapted to serve as a liquid reservoir, a flaccid container within the case, means for creating vacuum within the case in and around the flaccid container including an inlet communicating with the case, means communicating with the liquid reservoir for discharging liquid on a surface to be cleaned, and means communicating with the flaccid container for drawing the liquid and included dirt from the surface to be cleaned into the container under the influence of vacuum whereby the flaccid container can fill and expand with used liquid at a volume rate essentially equal to the rate of depletion of the unused liquid, within the same space of the outer rigid reservoir.