Cleaning Tile Grout: Bleach or Not to Bleach?
How should you clean grout in the shower? Bleach will often be recommended, as it is very effective on white and light grey grouts. However, if your kitchen or bathroom has black or another coloured grouting, bleach should be avoided as it will make the grout fade. If you do apply bleach, rinse your tiles afterwards with cold water only, as warm or hot water will only intensify the vapours. Be sure to ventilate the room and wear rubber gloves when handling any bleaching product, and also ensure that you read the instructions on the label before applying it.
An alternative is oxygen bleach, a bleach compound that comes in powder form. Remember to follow the directions on the label and to test this product on a small area first before continuing. Mix equal parts oxygen bleach with warm water, let it dissolve, and apply to the grout. You can either pour it on or apply it using a spray bottle. Afterwards, scrub with an old toothbrush, rinse with cold water, and wipe your tiles dry.