Try whink rust remover, in brown bottle, found on most grocery stores.

This has worked for me:straight lemon juice, let it sit, then scrub off with mild abrasive. I use one of those "Dobie" kitchen cleaning pads and either scouring powder or baking soda. .

Thanks, I have lemons in the house so I'll try that first then the Whink if it doesn't work. THANKS!