Pour 1 squirt of dish soap into a spray bottle with 3 cups of warm water. Twist the lid onto the bottle and shake to dissolve the soap.
Spray the soapy water over the entire shower, and let sit for 30 seconds.
Scrub the marble with a damp cleaning rag to remove buildup.
Rinse the shower with fresh water.
Dry the tumbled marble with a clean, dry cloth. Wipe in large, circular motions that will prevent water spots plus restore shine to the tumbled marble.