Cleaning 1.25" photometrid filters is a pain. Has anyone tried Eyelead Sensor Gel Sticks? Expensive, but worth the cost if they are safe for my BVIc filters and my CCD window. Available through Amazon and probably any well stocked camera store.
A short review of the web shows that some people got in trouble with the filter stack of their DSLR, incorrect use ? compatibility problem with the DSLR coating, DSLR defect ? Unclear...