It is a clear solution so it does not change the color of the tile or grout, but it will give some gloss to the surface. Paint the sealer on the dry tile or grout, being sure to cover all crevices and cracks. Let it dry and apply a second coat. Thereafter, apply one coat about every year to maintain the seal. The sealer prevents dust from grout being tracked around the house, and makes cleaning very easy with a damp mop.
Some people prefer to use a wax over the sealer.
Experiment with a sample tile or an inconspicuous corner as some waxes leave a streaky undesirable finish. Dingy grout between tiles can be brightened by scrubbing with hot suds, then apply a diluted solution of chlorine bleach. Repeat procedure, keeping tile wet 5 minutes. Do not use scouring powders or other abrasives which can scratch the finish. Remove mildew by cleaning with a dilute solution of chlorine bleach in water, following label directions on bleach.