FIG. 1 is a perspective view of a flexible cover for a sponge mop showing our new design, shown in its intended use with the broken line showing of a sponge mop being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof, the rear being a mirror image;

FIG. 4 is a bottom plan view thereof; and

FIG. 5 is a side elevational view thereof, the opposite side being a mirror image.