[header] How to clean a ceramic sink without chemicals [title] Apply lemon juice or vinegar to any stained areas. [step] These mild acids are especially effective at removing rust stains. If you use lemon, you can either squeeze the juice onto the stain or gently rub the stain with a lemon wedge. 
Alternatively, pour a little white vinegar on the stain. [title] Allow the cleanser to sit for a while.