We have Restoration Hardware polished nickel knobs and pulls in the kitchen, and I've been noticing (for longer than I should admit) that the ones on the upper-upper cabinets that don't get used or cleaned much are very cloudy.

I just tried to clean them with limited success and I'm wondering if anyone has any tips. Water with Dawn, 409, and white vinegar (separately, not mixed together!) didn't do much, while Brasso and silver polish did better, but even those left the knobs noticeably cloudier than the ones on the drawers and cabinets we use regularly. I hope they aren't permanently marred from heat and whatnot up there.

On a related note, is it possible to do a search in one discussion forum anymore? I tried searching for help on this topic, but it searches ALL discussions and brought up tons of useless results.