We've all had those sinks that it seems no matter how much you've cleaned them, they get the Hard water deposits on them and you can't get it off. The only answer is to get a new faucet, and that's pricey sometimes depending on what kind of faucet you have. I've found a link that suggests just a little time, an old rag of some sort, some distilled white vinegar, a bowl and soft scrubby pad that won't scratch the faucet.