[geoschmo]

Certain types of plastic react very poorly to alcohol. Other types aren't affected at all. Your guy could very well have used them on his with no problem if he had the right kind.

I would want to know for sure what an LCD screens is made of before touching it with an alchohol wipe. If the outer surface is glass you should be ok, but if it's some sort of polymer or if the glass has an anti-reflective coating you could be in trouble. You should always refer to the manufacturers instructions. The LCD manufacturers, not the wipe manufacturers that is.