The only thing I have ever used in the past 15+ years to clean my lenses and filters (although I have not used a filter in about 10 years) is the Ilford anti-stat cloth. These cloths (the orange ones) were designed to wipe down film after they were dried off, but have become a favourite among photogs for cleaning off lenses, filters, eye pieces and LCDs.
You can find them on Amazon.com here
http://www.amazon.com/Ilford-Anti-st.../dp/B0000AE6AG
Happy Flying
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Fish