Ordinary cleansers won't make a dent in mold or mildew. Spray with a specially formulated mildew treatment, then scrub with a grout brush or a toothbrush. Let sit for 15 minutes, then rinse and repeat if needed. When the walls are dry, give the grout a final misting with the mildew formula for prolonged protection.

You can prevent mold buildup in damp bathrooms or those in humid climates by running a squeegee over the tile after a shower. The same trick will eliminate soap buildup on glass shower doors.

Enviro-Magic Mildew Stain Away Spray, $10, 800-832-5645. Grout Brush from Oxo, $6, www.oxo.com, 800-545-4411.