Porcelain tiles are extremely resistant to staining due to the low porosity. Metz porcelain tiles are unaffected by all janitorial cleaning products even in concentrated form. Cleaning products containing acids, alkalis, bleaches, solvents can be used without concern for the tiles.

Metz strongly recommend that proprietary floor cleaners be used as these are specifically formulated with beneficial properties for this task.  General purpose detergents and other cleaning products may perform poorly and leave residues that can build up and trap dirt.

Slip resistant finishes can be as effectively cleaned as smooth surfaces, and with the correct tools just as easily.

Metz recommended method is:-

Most problems with floor cleaning relate to poor rinsing, which leads to a build-up of detergent residues.  These residues in turn trap more soiling.  This cycle is easy to break with an improved rinsing step. For severe build-up a deep clean with a different detergent and thorough rinse will restore the floor.