Lem:
The scum forms when calcium sulphate reacts with sodium in the soap, I've
never had this problem in any of the places I lived. I don't touch my
screen and I stopped smoking years ago, so I rarely need to clean my
monitor. If I had to clean it often I would probably use a cleaning spray,
but dish soap and water works fine for me, you do need to dry the screen
with a paper towel afterward.
For screens (and windows) rather than a paper (or cloth) towel, use a
squeegee (sp?) (memo to self: too many ()s)
It's hard to get glass completely clean with a cloth or paper towel; a
lot of the dirt just gets smeared around. The squeegee strips away the
water/solvent/soap/gunk from the glass where it can be removed from the
rubber blade with a paper towel.
Look for the little 3-inch wide models. Very, very handy for doing the
insides of car windows, as well.
Note: Be careful if using it on a monitor screen. A film of water that
doesn't run/drip by itself will collect in front of the squeegee blade
into a small puddle that *will* run/drip. Work from bottom to top and
keep the angle of the blade tilted towards the vertical mid-line of the
screen where the overflow can be caught with that handy paper towel.