Just had new tile laid on the bathroom floor. The installer did a good job but his helper apparently cleaned his tools in the bathtub and left a large mass of thinset or mortar in the bathtub. Unfortunately, I did not find it until the next day. I was able to remove about 90% of the stuff, but there is a large gray spot about a foot in diameter and an area about half that size with pronounced black streaks. I think the stuff was modified thinset.
I did a web search, but got lots of sites that tell me how to remove grout from around the tub when removing the bathtub - but nothing on getting the stuff off the bathtub when it is spilled inside.
I have some Bon Ami that I am about to try, but I would assume that even Bon Ami is likely to remove the sheen from the porcelain if I scrub too long and hard. Anyone have any magic pixie dust to make this stuff go away?
The guy behind the counter at the tile shop suggested trying X-14 cleaner, which I will try and locate. I have my doubts, however, that it will do much good. Probably try some strong oxidizing cleaner to ee if that will at least lighten the dark gray areas.