HOLY CRAP! I just bought a generic Magic Eraser at Meijer, because I had some tough spots on a few surfaces. I was very doubtful of its abilities, but it was only a few dollars and the various cleaners, including Lime Away, weren't doing the trick.
The first spot I tried was a few wierd blue stains on the side of my toilet bowl that looked almost like ink, a little present left by the plumber. They just weren't coming off. Also, there was some serious water residue on parts of my tube. Not cool either.
The little eraser is a light, fluffy sponge when you pull it out. I dampened it a bit, like the directions said, and went to the toilet. About a half-dozen scrubs later, the wierd blue stains were totally gone. I just sat there wide eyed in disbelief.
I thought I'd try something a little more substantial and took it to the tub. Earlier that afternoon, despite using every cleaner and all the elbow grease I could muster, I couldn't get the stuff off. Some work o' the magic sponge-wand and the stuff started coming right off. It was fantastic. The surface area was larger and rougher however, so the sponge was starting to show some real wear and tear.
I was so happy with this thing I almost called every person I know just tell them know about it. Instead, all of you get to hear the news! Lucky you!
But seriously, wall marks, dingy tiles, water marks, scar tissue, cancer, guilt.... it does it all....