This can be used to clean bathrooms, showers, bathtubs, tile, grout, fiberglass, chrome wheel rims, boats, outdoor furniture, stainless steel, ceramic sinks, and more. This is non-toxic, safe against septic systems, and free of bleach, acid, and harsh chemicals.
Promising review: "Have you ever seen the movie The Santa Clause? There's a scene where Tim Allen's character shaves away his white beard and then ~WHOOSH!~ it reappears instantaneously. That's basically my bathtub and soap scum. I've tried many products to keep it at bay, but this is the only one that has ever really worked. Not only does it have a cute dog on the packaging, it also allows me to (easily!) wipe away dastardly soap scum without having to use a lot of muscle! Which is great, because I don't exactly have a lot of muscle to use." —Mallory McInnis
Get it from Amazon for $18.88.