IN the comments of this FB Wonders of Vinegar video that I
For a super clean shower and bath tub mix 2 cups white vinegar, 1/2 cup of Blue Dawn dish detergent . Heat vinegar until hot not boiling add Dawn and put into a spray bottle.Shake to mix well.(DO NOT ADD WATER TO THIS) Spray shower and tub real good and let it set . The dirtier the longer the solution should set . Usually no more than a couple of hours but over night won't hurt anything. You won't believe your eyes. Use only the Blue Dawn. Happy cleaning.
The friend who posted this commented: I bought a dish scrubber (the kind that you put soap in the handle) and put this solution in it. I keep it in the shower, and give the tub a scrub every few days. It stays clean; no lime buildup.