If its just surface dust, usually a lens cleaning cloth works for me - the alcohol swabs I thought would have worked as I have used them successfully before on scope stuff & previous job using telescopes). If I have something that is very difficult to remove I usually go with acetone. This is harsh though and I caution it's usage - my favoured method was a cotton bud dipped in the stuff, wipe ONLY on the glass affected and avoid getting on rubber/plastic pieces (we were always told by our microscope mechanic is degraded these parts - even though he mostly used acetone as well). If you don't have acetone nail polish remover is almost all acetone & makes a great substitute. Avoid the herbal / environmentally freindly nail polish as they don't have the acetone.
A lens pen works well for me aslo (for the occassional bad fingerprint).
I use a lense cloth gently from time to time for dusty spots (from when EPs dry out after getting dewy).
For some very old/grubby eyepieces, I used cotton buds dipped in Bintel cleaning for tough spots. If using cotton buds, avoid using too much solution, and soak it up with a fresh buds before it leaves "drying" spots.
Best of all, I started putting the dust caps back on my EPs when not in use ... avoided most dust and foam/lint from getting on the glass in the first place.
My dilemma recently purchased a finder for my scope. A Stellarvue 10x60 with right angle eyepiece holder that comes with a reticular eyepiece. Unfortunately arrived with a dusty/ dirty eyepiece even though had lens caps. I tried everything even dismantled the eyepice down to the lenses to get the dust and grime off but tiny little specks remained. I got fed up and returned the eyepiece for a replacement. Even the replacement one received had tiny specks on it (naturally not noticeable at night) I might give the dust pen a go. Thanks to all you all deserve fine viewing, "May the clouds part and the stars shine brightly upon you"
