I started doing this and will never stop! My tub & shower are always spotless-so simple. Simple shower and tub cleaner: fill wand half vinegar and half dawn dish soap. Wet surface and scrub. leave in shower & wash while you are already in there
Dishwasher soap - Baking Soda & Borax (all-natural household cleaner, in the laundry aisle) Mix together equal parts of each. Use just like a commercial powdered detergent, approximately 2 TBS per load. Each load will cost you pennies.