Just yesterday my husband mentioned that his shower was icky, so I decided to give it a good cleaning. In an effort to save time/money/effort I did a quick search on the net, and found all the usual ideas, plus one I had not heard before. Listerine mouthwash! This sounded so preposterous that I of course had to try it.
I had a big bottle of the Wal-Mart generic version, and decided I'd sacrifice some in the interest of science (or maybe it was laziness.) Anyway, I wet a rag thoroughly and slopped it on, re-wetting the cloth as needed (this was a microcloth.) While each small wall was still very wet, I quickly scrubbed the whole surface down with a large cleaning brush. I didn't have to scrub hard. I could feel the surface tension releasing, and knew it was as clean as it was going to get. Well, guess what? It smelled great and was nice and clean. I used some Barkeepers Friend on the shower floor, and was happily done! YMMV, but it worked for me!