I have a Reflex Synchro that must have been owned by a heavy smoker at one time. I've been able to clean most of the crud off of the exterior and interior, but I can't figure out how to clean the inside of the lens out. I tried setting it to B and putting a Q-Tip in, but it is too large to fit in the hole. Is there any way to take the lens off from the outside so I can clean it?