Terrible, that I actually had to find a forum because this is driving me crazy! I have two black toilets(1200$) all of a sudden they have a white ring in them. I have tried everything to remove this ring. In the old days(white toilet) I'd fill the toilet with clorox for eight hours and that would be the end of those rings(of course white toilet/black rings...I have NEVER found one person who could tell me what I can safely clean black toilets with. If anyone can help, I'd so appreciate it. Thanks