My DSLR finally arrived tonight, along with the Kenko(Hoya) Pro1D multicoated "wide band(?)" circular polarizer. Of course, the polarizer's package had popped open and it was loose in the box. I don't see any scratches or damage, but there is a bit of dust on it now. I have two questions: 1. Are there any special precautions in cleaning a multicoated filter? Should I use water or lens cleaner or alcohol or my breath or keep it dry? Are glasses cleaning tissues acceptable for camera gear? 2. When looking through the filter and turning it, I see a change in the character of the light coming through. I would expect that for a linear polarization, but I thought circular polarization was meant to prevent this. Is this filter defective? If not, will that cause problems with lenses that rotate while focusing?