Removing Grout stain or grout haze from glazed tiles such as ceramic and porcelain can be relatively straight forward, for cases in which the grout stain is on natural stone you have to make sure that Grout stain remover is not used on surfaces that are calcareous, sensitive to acids (e.g. stainless steel, chrome, enamel etc), Surfaces to avoid using on are Marble, limestone, travertine, granite terrazzo and encaustics.
For mild cases and on absorbent tiles:
Dilute 1 part Grout stain remover in 4 parts warm water, apply with a cloth or sponge wrung out in the solution, then wipe off thoroughly with a clean damp cloth.
In more severe cases:
Dilute 1 part Grout Stain Remover in 1 part warm water, Apply liberally and spread over surface of tiles. If necessary, agitate with a scrubbing brush and leave to react for 5-10 minutes, keeping wet with additional Grout Stain Remover solution. Mop up and rinse thoroughly with clean water.
In extremely severe cases:
Use undiluted and agitate with scrubbing brush or mechanical scrubber if necessary. Neutralise treated surface with clean water after use.
Epoxy Grout Residue is cleaned differently to the above steps and requires a different product and method to clean the residue.
Epoxy Grout is made up of two parts, a resin and a hardener, the hardener also contains a detergent in it to improve work-ability and the cleaning of the residue. Epoxy grout can discolour porous surfaces as can the cement based option, its best to seal any porous surface before grouting.
The foregoing advice, whilst given in good faith and from experience gained in various installation situations is for guidance purposes only. If in doubt at any stage, experiment before proceeding further or seek further advice. Neither the supplier nor the manufacturers will be liable for any dissatisfaction resulting from these instructions nor will they in any circumstances accept responsibility for any damages.