Wet wipes, the ones from KFC or the cotton soft baby wipes from Asda.
Whilst still wet, wipe with a soft tissue.
Worked on mine (screen, that is) for over five years with no problems.
Can't remember the name of what I use right now, a small bottle of cleaner just for lcd televisions. About £20 a small bottle, but seems to last ages and does a really good job.