I have to use vinegar on the deposits. It's that constant stain that ticks me off. LOL!I occasionally plug up my bathroom sinks and pour a little clorox in and let it soak for a couple of hours. We also have hard water, so using vinegar or bleach (NOT AT THE SAME TIME) works wonders.
I'll try the bleach and a toothbrush. If that doesn't work I will look at these other ideas.