Hello, I took my UV filter off today and noticed a mark on the lens. I took the filter off very carefully so I am sure it wasn't made by me touching it! It looks like an oily fingerprint mark, so I wanted to try and clean it off. What do you recommend using for cleaning the lens? Searching the internet seems to suggest using lens paper, microfibre cloths, or "lens pens". These seem suited to larger lenses on DSLRs and such, so I was wondering what everyone here was planning to use to clean their lenses Thanks!