If you are trying to remove hard-water spots and lime deposits from shower walls and glass doors, here's a formula to help you fight grime. Sodium carbonate is the base for many cleaners and is the main ingredient in washing soda. It'll dissolve crusty white lime deposits and hard water spots. If it doesn't work, try a squirt or two of liquid toilet bowl cleaner. Wear rubber gloves, protect your eyes and avoid fumes. And that's the On The House tip for today.