Celestron Ultima 2x Barlow & cleaning eyepiece lenses

[Terry Scope]

I bought a second hand Celestron Ultima 2x barlow quite cheaply. It has what appear to be marks (probably dew marks) on the surfaces. This causes me to ask 2 questions. 1/ what can remove these marks? I used a micro-fibre cloth and it seemed to remove the marks but they came back. 2/ I took the lenses out to clean them. I took a great deal on care to ensure I knew which way they go back. Well I did for the 2 outer elements!! The inner element was tricky to get out so I gently tapped it out onto a cloth and promptly watched it roll off the table onto the floor (carpeted luckily) so now I'm not sure whch way around it should be. I think I got it right but can anyone have a look at theirs and tell me if it is obvious which way round it should be.

[glowjet]

Baader Wonder cleaning fluid from FLO is one of the best, I do not think it should have been necessary to remove the inner lens, as these are assembled in a dust free atmosphere, if you reassemble it and it does not work correctly you have it the wrong way round so you have only two possibilities, best of luck

[spaceboy]

I've found with plossls the curved side of the lens always face a curved lens and the flat sides often faces the eye depending on how many elements there are. I'm not 100% if this is the case with barlows though but hey what you got to loose. FYI the mark would have no doubt come off with a few breaths and a VERY gentle wipe of the micro fiber. I had a mark on a brand new lens recently and this simple method did the trick.