Baking soda works well. Apply with a wet sponge.

duk I just saw your post I'm new here but thought I'd give my 2 cents worth.

Scrub free and Tilex both makes a decent shower cleaner. The Scrub free has a little bit of wax in it which is wonderful but I take it a step further.

I live in an area with VERY HARD WATER. So about every 6 months I get out the Lime-Away and really really scrub the shower walls down and get all that lime off. In 6 months even with regular cleaning I can feel the lime starting to build up but don't see it yet.

OK I make sure I got all the lime off and the walls and sides of tub and bottom are CLEAN. Then I get out the car wax most any car wax will work I think right now I have Turtle.

I wax the sides of shower and tub but not the bottom or the side of tub top where we step in an out of the tub. Don't want those to slick don't want no one to slip and fall.

After waxing I've found I can spray on the cleaner let it run down the walls to the bottom of tub while I do the rest of the bathroom then spray off the cleaner and I rarely even have to scrub the shower. About once every couple of weeks I'll run a rag over the sides of shower and tub takes all of 2 mins that is more or less to just shine the sides. Every once in awhile I'll run across a glob of conditioner that was slung on wall but that is rarely.

LOL it's taken me longer to post this reply than it does to clean my shower.

With waxing the walls it prevents lime and soap scum from building up because the walls are slick and everything tends to just run off and down the drain. It takes a bit of effort to wax the shower a couple of times a year but it saves me a bunch of time and effort between waxings.