Bleach is a bleaching agent which can improve the stain removing of good laundry detergent, but as I read somewhere, bleaching is no substitute for proper laundering methods. While caustic, it is not a surfactant and is not a cleaner by itself. Greasy discoloration will not be removed with bleach. Either STPP with the detergent or that gel (Shout or Spray & Wash?) applied as a pre treater is best for grease. My favorite discovery about bleach is that when mixed half and half with water and applied to the tile and grout above the tub or in the shower and allowed to dry will not only result in snow white grout, but after the second or third time that this is done, no more dark stuff grows in the grout. Of course, some people do not like the swimming pool smell of the chlorine, but it brings happy memories to me and smells really clean so I like it.