The reason the mineral and rust remover isn't working is because it's not rust, it's pee! Dried urine! Gross I know, but sadly true. I know this because I potty trained 3 boys with very bad aim and we are currently living under a strict water conservation effort due to the droughts in the south east. We don't flush as often as we used to so that ring is appearing in our toilets!

Your new best friend is a cleaning product called "Sno Bol" (also mentioned in the great toilet post from a while back) This stuff can be hard to find, only one store near me carries it. When you use it, read the directions carefully, wear gloves and keep an old rag handy to wipe up any spills. It will burn your skin! It's thin and you'll think it won't possibly work, but squirt it in there, wait a few minutes then wipe with your toilet brush. The ring will wipe right off.

Take off the toilet seat and treat the grungy areas on that (I throw mine in the tub) and while it's off, clean the bolt hole on the toilet. Within 15 minutes, you'll have a clean toilet and seat! Once it's good and clean, you can keep that ring from reappearing by cleaning it regularly with your favorite product. I like scotch bright toilet scrubbers for in between cleaning but don't mix these with the sno bol or you'll have that deadly bleach+acid chemical reaction that gives off chlorine gas in your bathroom!