The edges of grouted tiles covering a floor serve as hundreds of little squeegees. These edges “squeegee” off whatever is on the dust mop and/or wet mop and that “whatever” ends up down in the grout. When the water evaporates, a residue is left behind. If the water is dirty, dirt and detergent residue build up in the grout. If the water is relatively clean but the cleaning solution leaves a residue, this leads to build up as well. We typically live with this until someone says “enough” and the supervisor is faced with an extra task added to an already overloaded schedule.

How do we solve this problem? Two things: deep clean the grout lines and keep buildup from reoccurring.

Grout lines can be deep cleaned in one task or cleaned gradually. Deep cleaning in one task requires a strong cleaner, contact time, agitation, removal of the dirty solution, and, finally, rinsing the floor. All this is followed by the instructions we hate to read — “repeat if necessary.”

To complicate things, often the grout has become discolored, or stained, by the extended contact time with the dirty residue. Usually, an acid has been used to etch the grout in an attempt to get the grout as close as possible back to the original color. Fortunately, chemical companies have brought hydrogen peroxide into many new formulations that can remove the stain without etching. 

Hydrogen peroxide is our transition into gradual cleaning, because we now have daily cleaners that leave no residue and gradually deep clean the grout lines. These cleaning chemicals utilize hydrogen peroxide in their formulations to boost cleaning performance without damage to the grout. A word of caution here: Because many of these cleaning chemicals have a pH below 7, they are not designed to be used on polished marble.

Using these new cleaners solves our problem of residue left by chemicals. But if we use them with dirty mop water, we are back to square one. That’s why we need to bring in microfiber.

A microfiber mopping system that uses clean pads in each room instead of the same dirty mop head will do wonders for the floor and grout. After cleaning each room, janitors should change the mop head so they won’t be leaving any dirt behind in the grout.
Together, hydrogen peroxide based cleaners and microfiber mops can clean floors without creating future grout problems.

Skip Seal is a trainer and consultant with more than 30 years management experience in the cleaning industry. He is a LEED Accredited Professional and a Cleaning Industry Management Standard (CIMS) ISSA Certification Expert (I.C.E.). Seal and his team offer support across the country with sales and operation analysis, new market penetration, and sales training. He can be reached at