Having dirty eyeglasses is maddening. You find yourself trying to look through smudges at your computer screen, or wiping off a fallen eyelash only to add another fingerprint to the lens, not to mention the unbelievable number of pet hairs and nose smudges dogs and cats leave behind. Why do animals find glasses so fascinating?

In desperation, you probably pick up the hem of your shirt or a paper towel to wipe them clean — only to find you've somehow made them worse. That smudge in the center of the lens now spreads from one edge of the frame to the other and if you're lucky, there's a constellation of scratches right in front of your eyeball too.

It turns out that keeping your glasses smudge- and scratch-free is both cheap and easy. You need to wash them, gently. It's something you can do every day without harming your eyewear, whether you wear inexpensive readers from the drugstore or designer frames with coated progressive lenses.

Here's your new routine for keeping your glasses clean:

If you really want to get your glasses super clean, here are a few more advanced cleaning tips you can also add to your routine:

There are a few things to avoid, like shirttails, paper towels, tissues and anything else that isn't a cloth made for lenses. Those things can scratch the lenses, which cannot be cleaned away.

Don't use glass cleaner, despite its name, as it can remove any coatings that you've paid to have on your lenses. You may be tempted to use something with acetone, like nail polish remover, to cut through the smudges, but that is far too harsh for glasses. Ultrasonic cleaners seem like a good idea, but they can scratch lenses too. Soap will do the trick, for real.

When we say cheap and easy, we mean it. The best dish soap for the job is as plain as possible, without extra cleansers or anything abrasive. The most basic dish soap on the shelf will do just fine.

A lot of people can't remember if they're nearsighted (aka myopia) or farsighted (aka hyperopia), but it's easy enough if you think about the words. Nearsighted people can see things nearby easily, so their glasses adjust their vision at a distance, like for driving. Farsighted people can see things far away easily, so their glasses adjust their vision for close-up things, like books and screens.

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