I have glass shower doors (curved of course). Over the years I have struggled with hard water and soap scum (hubs is a bar o' soap man). I've tried nearly every product out there - most require liars of scrubbing and breathing the fumes.... I was talking go a friend in town who has similarly hard water like ours (yes we have a treatment system for the house) she tried and lied the Dollar Tree a Totally Awesome version of Kaboom. I was at DT this afternoon and figured what the hell. It's a buck, if it doesn't work great I won't buy it again...it works ok. I will try it next week and see if I like it any better then. Here is what did work though on the doors at least. A paint scraper (with the razor blade). I will be touching up some windows this summer and wanted some little scrapers and DT has them 4/$1. I don't know what made think if this now - maybe it was scraping my town beach pass off my old mini van windshield this morning so town hall will give me a new one for the Prius (rather than buy one). Well - not to gross anyone out, but it worked great for the soap scum (it's been 3 weeks since the doors had a hearty scrubbing (the rest of the shower has had a quick weekly wash down). The stuff just came off! So I took an hour and did the glass portion of the shower - the walls are a composite so when I hit the paint store thus week I will hunt down a good plastic version scraper.
After the scraping I used the DT Kaboom and scrubbed the rest of the shower and the kids tub which was in desperate shape - I did notice it's not stellar, but like I said - it's been a good 3 weeks since the bathrooms have had a good through scrub down. Maybe it's a good enough produce god weekly cleaning....not nuts about the fumes from it though - so I may go back to my Lysol Power & Free to avoid fumes. Everyone freaked out when I made my own lemon & vinegar natural cleaners - wimps!