Since day 1 my circular polarising filter jammed on my step up ring. Finally it became stuck fast. This happened at an inopportune moment as I was just off on a trip. I had no choice but to buy a new filter. I need to buy a new step up ring so that I can use my nd filters. Should I risk buying the same type of aluminium step up ring or buy a brass one? Does any one use anything on their filters to stop jamming on their lens?