How to clean rust coloured spots off toilet hinges?

[wildstrawberryplace]

I don't know if they are stainless steel (not very stainless if so!) or chrome - chrome I think... they have rusty looking stains on that seem to be shifting when scrubbed with a tootbrush and bit of toothpast (tip from google). Surely there is a quicker way - WD40?

Bar Keepers Friend is good for rust spots on our SS radiator so it might work in principal. Bleach and cleaning products is what turns SS rusty.