Interesting fact of cleaning learned serendipitously:
Apparently Spray N' Wash, in addition to its laundering uses, is awesome at cleaning showers n' tubs. My mom randomly discovered this when leaving treated car mats in the bathtub to soak and coming back to patches of clean in the then completely rust-colored tub. Now it is its original color, and even the scum on the glass doors is gone. The spray did not smell as awful as most cleansers you would use for such things and is most likely cheaper (definitely more versatile). She gets it at Save-A-Lot for $2-3, which while significant is not a whole lot for cleaning-type products.