[Wavytone]

Syd,

1. Use a blower brush (camera shops) to blow away any grit/dust. DO NOT scrub with a fabric or kleenex.

2. As per Andrews advice, assess what's on the lenses as to whether its greasy (usually).

3. Using a cotton bud (the things women use to clean their eyes) dip this into solvent and then wipe the lens. Try to use as little as possible - using too much means the liquid will seep into the lens cell and contaminate the inside surfaces of the eyepiece and the only way to fix that involves complete dis-assembly - see 5 below.

Ideally use isopropyl alcohol (visit your local chemist or ask Bintel), but in a pinch "Windex" works well, as does water with dish-washing detergent - just as good at removing greasy marks - but this has to be flushed afterwards with distilled water. Scotch whisky or OP rum should work nicely too, for that matter, and cheaper than isopropyl alcohol. Acetone is not recommended - it leaves a waxy scum.

4. Modern lens coatings are quite tough (I wear prescription specs with coated lenses) and its quite safe to wipe eyepieces gently. The best material to use is a well-washed cotton hanky, or a damp (not sopping wet) Kleenex tissue.

5. If you wet the eyepiece so badly liquid gets inside this is a REALLY BAD THING. The eyepiece will fog up internally every time it cools down, and quite possibly you'll have liquid floating around inside if you did a really bad job.

The only way to fix this is to dismantle the eyepiece and carefully wash and dry every element then reassemble.

6. If you want to clean a bare lens, holding it under flowing hot (ideally boiling) water will remove most things with no rubbing at all.

But remember this: An eyepiece that has been dismantled never works as well again as it originally did, when new.

So look after the things.

You have been warned.