I use the one use Zeiss optical wipes. I was recommended them by a guy I know who's an astrophysics researcher, he uses the them to clean the optics of hundred thousand pound telescopes. His reason was because they are one use, reusing a cloth could have dirt on it which in turn could cause scratches.
The optical wipes are slightly wet when first opened but do dry off quickly if you wipe too long. The best way is not to get smearing in the first place, lens hood are great to protect the front element.