Sweep or vacuum the tiled area to remove loose dirt and debris
Mix a pH-neutral tile and grout cleaner according to the label instructions
Apply the cleaner to the grout lines and let it sit for the recommended time
Scrub the grout with a stiff nylon brush or grout brush
Wipe away the loosened grime with a damp microfiber cloth or sponge
Rinse the area with clean water and dry it completely
Let the grout dry fully before sealing
Choose a grout sealer suitable for your grout type
Apply the sealer to the grout lines with an applicator bottle, brush, or small sponge
Wipe excess sealer off the tile surface before it dries
Allow the sealer to cure for the time specified by the manufacturer
Apply a second coat if recommended by the product instructions
Avoid wetting or using the area until the sealer has fully cured
Reapply grout sealer periodically as needed