- White vinegar
- Old t-shirt or cloth
- Green & yellow sponge
- Soak cloth or old t-shirt in vinegar.
- Wrap or lay the soaked rag onto the hard-water deposits and let sit for an hour.
- Remove the rag, and gently scrub with a soft yellow/green sponge.
- Repeat steps above again for stubborn spots. (From Simplemost)