I absolutely swear by my Mr. Clean Eraser. I did recently use it on my
fiberglass shower stall floor and it did clean up the soap scum
wonderfully better than any other product I have ever tried (i.e. Dow
Cleaning Bubbles, Clorox Cleaner, Tilex etc...). I do live in an area
with hard water.
On a side note, I was actually going to repaint some walls in my
house, and did not have to after using the Eraser. The walls I have
painted are semi-gloss, and it worked excellently. However, the walls
the previous owner have painted were not semi-gloss, they were a flat
paint, and when I used the Eraser on those walls some paint did come
IMO, it is worth giving the Eraser a try.