Old CRT-based TVs and computer monitors were tough. For the most part, you could spritz them with Windex and wipe them down when they got dirty. I never had a problem getting a TV clean.

But now the world has moved to LCD, plasma, and other flat-panel technologies. And with laptops especially, screens are very prone to getting filthy because people just can't keep their fingers off of them. But how do you clean an LCD? Here's what I do.

For starters: No Windex. While LCDs have glass inside them, they are coated with an optical film, and the chemicals in glass cleaner (namely ammonia) can damage that film. That film can also be easily scratched, so don't use paper towels or any dry cloth other than microfiber or other lint-free cloth either. Also, as with a TV, be sure to turn the device off before you try to clean it and until it is totally dry, as any liquid can cause a short.

Personally, I now use a commercial LCD screen cleaner (the kind that comes in a spray bottle and includes a special cloth) for all my LCD monitors, LCD TVs, and laptop screens. I've never had a problem (though I've read reports of people who've had discoloration due to these cleaners), and my screen always comes out sparkling. You can usually find them near checkout at any electronics or computer store, or get one online. Check out these examples. That Belkin cleaner looks just perfect. Klear Screen is also commonly recommended, but it's much more expensive.

What I do not recommend are the prepackaged wipes that are moistened with cleaning liquid. (You often get a second wipe for drying.) In my experience, these always leave residue on your display, and I don't trust the dry, paper wipes not to scratch the screen. After using them, I find the screen rarely looks much better than before I cleaned it. Since I switched to the spray-bottle products, I've been much happier with the results.

If you want to save some money, you can try mixing your own ammonia-free LCD cleaner. You could start with plain water, but use distilled water. I've also read that you can add a little white vinegar or vodka to the water to aid the cleaning, but I've never tried that personally.

On a related note, you might also notice that laptops get smudged and dirtied by keyboards, which can happen if the notebook is poorly designed such that the screen actually touches the keys when it is closed. To remedy this, I cut up an old t-shirt and place it over the keyboard when I close it. It also makes for handy dust rag for quick tidying up.

Got special tips for cleaning your LCD or plasma screen? Share them below!