... polyester sponge,that is specifically designed forclean up grout. Designed to clean up grout, size as 5-1/2 in. Extra-Large ... of general cleaning tasks. Rounded corners help prevent "digging out" grout, and the hydrophilic cell design gives the sponge a high ... water-holding capacity.Cleans up grout during tile installationGreat for washing cars, boats and other cleanup ...