unless there is a smoker in the room on a regular basis then the screen should never need wet cleaned but only dusted with a microfibre cloth.
since you have already washed the screen using a dampened cloth and got a smudge,then you should now wash with hot water using a wet wrung-out cloth and immediately dry it with either kitchen towel or a glass drying tea-towel.
glass drying tea-towels can be had from any big supermarket. if you dont know what i mean then ask your mum or your granny!!
make sure that the screen is cold before you wet it or the moisture will evaporate and leave smears.
Well I've cleaned 2 LCD screens with a lightly moistened microfibre cloth - 17" and 37".
The 17" is my PC monitor & doesn need a moistened cloth becuase spots are left on the screen if I sneeze or blow my nose ! I may have very light smers left but at least it does a better job than using any other cloth.
The 37" had some light marks. Cleaned it again the way I suggested & it was fine.
You forgot dogs, small children, and also flies (which in this part of the world secrete a nasty residue that leaves dozens of little black spots on surfaces. Fly poo? Dunno, but it's 'orrible!).
I'm reading this thread while doing a search of the forums to find out what the consensus is on cleaning plasma screens. I've always used ultra-soft lint-free cloths ("Pec Pads") moistened with water, but I still find greasy marks (dog nose, and 'fly gloop') are almost impossible to get off without leaving a smear.
I've just spotted a recommendation for using a 50/50 Isopropyl Alcohol/water mix, and as I have a large bottle of Isopropyl Alcohol I might give it a try.
...And following on from the previous comment about the reasons you might need to wet-clean your screen, I'm also adding "plasma situated over an open fire" to the list! (Seeing how often the screen cleaning question get asked, might as well keep one of the advice threads going!)
Our plasma sits right over the fire, and the mantlepiece only projects beyond it by about 1cm. I checked thoroughly before mounting the screen that heat wasn't going to be a problem, and we regularly have the open fire going without any issues. Last night however, the combination of wind direction and a chimney over-due for a clean meant that a lot of smoke billowed out of the fireplace and up over the screen.
So, this morning I've had a fairly major cleaning job to do (after I'd done what I've been putting off for ages - and swept the chimney!). The centre of the screen had a large, quite greasy deposit on it from the smoke. I first tried some "AF Screen Clene Duo" wipes (bought a while ago off Ebay), which comprise a ready-moistened and dry cloth. Using this got some of the muck off, but wasn't terribly effective. In fact, I started to worry that the smoke had permanently damaged the screen's coating...
But with a bit more elbow grease, the remaining marks were dealt with and the screen restored to a pristine state. What I did was use the soft cotton gloves conveniently supplied by Quad with my L-ite speaker setup - for handling the speakers without smudging the highly polished wood (but any soft microfibre cloth would also do it) - lightly moistened with warm water, followed by polishing with a dry one.
So, chimney and screen cleaned, I can now relax in front of the Crimbo scheduling... "The Great Escape" yesterday, "My Fair Lady" today... And all the other repeats!