Oil-rubbed bronze has a smooth surface that naturally ages with time -- that's part of its charm. What's not charming is the easy damage oil-rubbed bronze sustains when exposed to hard water. Minerals in hard water negatively affect the oil-rubbed finish and create water spots if left on the treated surface. Daily and weekly maintenance reduces oil-rubbed bronze's exposure to harsh minerals and extends the life of the surface. Mild cleaning solutions are required to eliminate hard water without wearing down the fixture's surface; you should always test them in a hidden spot of the fixture to test for cleaning safety.
Pour 1 tbsp. of salt into a bowl and add 3 qts. of warm water to the bowl. Salt is a safe, natural cleaning solution that eliminates hard water spots without affecting the bronze's surface.
Dip the toothbrush's bristles into the cleaning solution and gently brush the bronze surface.
Rewet the toothbrush in the cleaning solution as the bristles become dry, and continue brushing in a circular motion to eliminate hard water spots.
Wet a soft cloth with warm water and wipe off the cleaning solution from the fixture.
Rub the oil-rubbed bronze surface with a soft cloth to remove moisture.