plasma's have thick glass with phospherus gases in it thats enclosed in each pixel.. you can't get to the gas unless you BREAK the glass..and still it'll be you can't hurt it chemically...just use non-oily or non-alcohol based cleaning material and you'll be fine.

lcd's have the "plastic like" cover on them. we only use monster screen cleaners on them at the store...but i'm sure there are a bunch of soft cleaning solutions for it. do not use anything with amonia or alcohol in it and you'll be fine.