Thank you so much for all your suggestions. You guys are awesome! I didn't have time to go shopping to get the cleaners you suggested, so I thought about what many of you said - elbow grease. So I slapped on a glove and got right dirty by sticking my hand in the bowl (toilet flushed, of course

). The stains were made of a thick mineral deposit caking the bowl. It looked dreadful and not at all civil looking! So I took my metal scraper, hoping not to scratch the porcelain. It looked like the porcelain was scratched with blackish-grey scratches. But I kept going anyway. There were some deposits I couldn't get to because of the angle of the scraper, so I took a hard plastic kitchen utensil to get off the rest, which also took off the apparent scrapes from the metal scraper.
So there were no chemicals used, although the disposable plastic glove is not environmentally friendly. I did use bleach to detoxify the kitchen utensil and scraper, which also isn't environmentally friendly. But the solution was as least toxic to me and the environment as possible. In case anyone else has this problem, here's a pic of the tools I used:
I'll reuse the plastic scraper only for the toilet now of course!

The metal scraper is clean now and good to go for all the other jobs it does - including cleaning my stove, which was recommended by you guys when I first moved here.
Again, thank you all for your help. You guys rock my world!
