u must keep clean water for wiping clean grout surface,or you'll recontaminate the surface with the haze.after a period of time,like in ur case you'll find in homedepot or lowes in tile section a scrub/sponge kit,cost around 7-10$they have different colour sponges with a plastic handle.black sponge is rough 2 clean &orange is delicate,& easy cleaning.plus i imagine its also determines with the surface itself,you wouldn't want to use the blk sponge for a delicate surface or you'llscatch it up!but its a usefull kit.P.S. i believe the sponge must be wet,at least i found it 2 work nicer.sponges are like a big scotch brite material 3inX 5in in size,good luck & im sure some1 else might have a different or better idea!