I used comet on my toilet seat and it rubbed the finish right off until it was black. I got a new toilet seat and though I cleaned it constantly because of my 11 year old, it still managed to get yellow stains underneath within a month. I cleaned it with Mr. Clean Disinfecting Bath Cleaner (6% Citric Acid, 94% other ingredients?- no phosphate) and it started leaving a white mark apparently disturbing the finish so I stopped cleaning it. The seat has chrome hinges so I don't want to use a hydrochloric based product since that would destroy the chrome. The whink appears to be for rust stains and these are not rust stains. Any advice?