This is MY shower. I tried everything that claimed to take off hard water stains, yet those nasty deposits just kept building up! Barkeeper's Friend is my new best friend! I used it on stainless steel in the kitchen, read a Pin and started using on my flat cooktop, and just happened to notice it labeled for plastics. WOW! I scrubbed, but nothing like other products, and this one actually worked!! The other great part is this stuff is inexpensive.