My customer’s granite tile floor has developed several white streaks. They’ve tried several things but they don’t seem to go away. What can I suggest they use to clean them off?

These white streaks may be hard-water deposits, which can prove very difficult to remove. Suggest that they try a sulfamic acid-based tile-and-grout cleaner.

CAUTION Make sure to let them know to NOT use sulfamic acid or any acids on marble. Acid will etch the marble and repolishing will be necessary.