Regularly clean the surface with a soft cloth, warm water and mild soap. Cleaning with vinegar is an effective way to lift grease. Either soak a clean soft cloth and wring out any excess before rubbing the tarnished areas, or make a warm water and vinegar solution to soak larger items in for 30 minutes or so before thoroughly rinsing. You can also use nickel cleaning solutions such as Rohl Flitz Polish.
2. Avoid using harsh abrasives or acidic cleaners, as these can damage the plating.
3. You should also avoid exposing the plating to excessive heat, as this can also cause damage.
4. Finally, you should periodically wax the surface of the plating to protect it from dirt and moisture.