I Just got my scope duracoated. I think I've got a problem now. When you turn the parallax knob you can hear sand grinding. Its not that bad , but it sounds like a pocket knife that has sand in it. The company sand blasted the scope prior to the duracoat. They did cover all the knobs, but I guess some dirt seeped in. Is there a way to take off the parallax knob and clean the dirt out? Will water, compressed air, rubbing alcohol work? If not, any ideas on how to clean it? I really don't want to send it back to night force. _____________