I live in an area which gets it's water from a well. It's great, but 100 years ago the area was a manganese mine. Now manganese is kinda like 'rust' in that it's pretty harmless, but it stains toilets something fierce. And these stains are -black-.
I have two perfectly fine toilets that look -gross- after 5 years. I've tried various 'chemicals'... including muriatic and no go.
I've tried pumice, which works better, but no matter what they say, it -does- remove the glazing... and that only makes the stains recur faster. They usually come back within a month.
SO AFTER ALL THAT: Is there a way to 're-glaze' or 'wax' those areas after I pumice off the stains, so that it's 'sealed' against further stains?