Use this simple technique to clean stubborn stains and dirt off of unglazed porcelain tile, using either an alkaline or an acidic cleaner. We'll also help you identify your tile type, so you know which cleaners to apply.
First, make sure you know whether you have glazed or unglazed porcelain tile. “Glazed porcelain typically has a complex design or veining pattern that only happens with a baked-on glaze finish,” says tile cleaning expert Troy Cantini. “Unglazed porcelain tiles will all look basically the same with monotonous designs and no shade variations among the tiles.” If you’re not sure, Cantini suggests letting water sit on the tiles for five minutes and then wiping it off. If the tiles darken, they’re most likely unglazed.
KlenzAll, an alkaline cleaner, tackles grease and grime.
Restore, an acidic cleaner, removes grout haze. Both cleaners are available at tile shops and online.
Clean glazed porcelain the same way you clean ceramic tile. Cleaning unglazed porcelain tiles is trickier. There are no industry standards governing porcelain tile quality, so you can’t be completely sure what you’re dealing with. For that reason, Cantini says it’s critical to test a cleaning product on out-of-the-way tiles before using it “to make sure your scrub pads don’t scratch the tiles and the cleaners won’t damage or discolor them.”
Cantini recommends starting with a soft, nonabrasive scrub pad and a good-quality alkaline cleaner like StoneTech’s KlenzAll to emulsify and dissolve dirt, grease and grime. “If you still see smudges, swipe marks or a hazy appearance, it’s probably a grout haze leftover from the tile installation.” In that case, he suggests using an acidic cleaner, such as StoneTech’s Restore, which will safely remove grout haze from tiles that are not sensitive to acid. “Again, test it first on an out-of-the-way tile to make sure the acid cleaner doesn’t etch the tile.