I dunno if this is necessarily the right forum for this question, but I figure one of my fellow darkroomies might know the answer... I have an Omega A-6 Custom Lab consenser enlarger. The condenser lenses appear to have a film of dust on them. Is it necessary, reasonable, and/or desireable to clean these lenses? And if so, is there anything I should be aware of before I bust out the screwdriver and socket set? Thanks.