Ian
My procedure is as follows. Firstly I only try to clean the objective lense as that is the one exposed to the air so get condensation that can trap dirt as well is muck from you eye and skin.
1. Use an air bulb (Eg this
http://www.bintel.com.au/Accessories...oductview.aspx ) to remove any loose dust etc.
2. Get a very clean cotton bud and spray some spectacle cleaning fluid (you can buy at any opticians) on the end. Make sure it is soaked.
3. Gently use that to swirl around the lense surface. Don't rub, just try to spread the liquid over the surface.
4. Leave it for a minute or so
5. Gently wipe with a very clean microfibre cloth (again you can often get these from opticians) until dry. Again don't press hard!
This has worked with all my EPs.
Malcolm