Brushed nickel's good looks last a long time, as long as it is properly maintained. Dried water spots show up on brushed nickel as much as they do on shinier finishes, so cleaning them ensures the spots don't end up as hardened mineral deposits left behind by evaporating water. Dry the fixtures with a soft towel after each cleaning, or any time they are noticeably wet, as it helps prevent spots and mineral deposits alike.
Wipe the fixtures down with a damp sponge, rubbing away any dirt, dried soap or visible spots. Buff the nickel with a soft absorbent cloth afterwards to prevent additional water spots.
Mix equal parts white vinegar and water in a small spray bottle as a treatment for hardened mineral deposits. Spray the solution directly on mineral deposits, which look white and crusty. Spray around the base of the fixtures as well, where water often accumulates and may lead to mineral deposits. Allow the solution to sit for 5 to 10 minutes, and then wipe away with a damp sponge. Dry the fixture with a soft cloth afterwards.
Remove the stubbornest of mineral spots with a treatment of pure vinegar. Pour some vinegar onto a folded paper towel and wrap the paper towel around the fixture, ensuring the vinegar touches the areas containing mineral deposits and difficult water spots. Secure the towel on the fixture with rubber bands or twist ties. After 15 minutes or so, remove the paper towel. Wipe the fixture down with a damp cloth, then dry it with a fresh soft cloth.