The methods for cleaning dirty tiles and grout used by many households using regular household cleaning products and equipment is often ineffective and labour intensive with short term gains, if any, and far removed from the efficient deep cleaning systems that can be used today.
The normal household grout is a dirt trap, it is a very porous absorbent cement based material and soaks up the dirt like a sponge unless it is protected with either a surface or penetrating sealer applied when the grout was new. Tiles that have an uneven, undulating or manufactured anti slip surface are also dirt traps that will not allow conventional cleaning to remove the dirt deposits because a mop or similar device only moves the dirt from one dirt trap to another and cannot extract it from the surface.
The most efficient system involves using a high alkaline cleaner that is not able to be purchased on the supermarket shelves. I generally use a concentration determined by the state of the grout I have to clean. Kitchens and shower cubicles usually have the worst grout and tile dirt followed by the bathrooms and high density areas. The alkaline cleaner is sprayed or liberally applied to the tiled area with a mop. The grout lines and tile surface is agitated using brushes and the cleaner is left to dwell for about 10 minutes. Extreme care must be taken on the application of this cleaner as it may react with metals and damage painted areas. This alkaline cleaner will penetrate into absorbent material such as cement based grout and bring dirt to the surface for removal.
Essential equipment involves a water blasting turbo cleaner and a wet vacuum cleaner. The turbo cleaner blasts water from twin rotating water jets within an enclosed dome that is attached to a handle onto the tiles and grout while the wet vacuum hose connected to the dome removes the bulk of the water. This system efficiently removes the dirt, dilutes the alkaline cleaner and prevents excessive water build up on the tiled area. The remaining surface water is vacuumed and the area is left to completely dry before allowing foot traffic or any further work such as the clear seal or a colour sealing process.
It is a good idea if the grout lines have been cleaned to the original condition without permanent staining to have the grout lines sealed with a penetrating sealer. This will help prevent the grout from absorbing dirt. Sealers are not the complete answer because they eventually break down from chemicals and are not completely water proof; however they will provide initial protection for the grout for a number of years.