It has been said that the only two things you can depend on in life are death and taxes. There is a third: if you own a pair of sunglasses, they will get dirty. There is no way around it. Sunglasses are a magnet for dirt, debris, baby slobber, sunblock smudges, makeup, and just about anything else they come in contact with. Keeping your sunglasses clean can sometimes seem like a full-time job.

Note that there are do’s and don’ts when it comes to cleaning sunglasses. Do things the right way and you will keep your designer shades looking new for as long as you own them. Do things the wrong way and you can have them looking like they came out of the trash can only weeks after buying them.

Below are the do’s and don’ts of cleaning sunglasses, compliments of Salt Lake City-based Olympic Eyewear. The undercurrent of all of their suggestions is this simple fact: no pair sunglasses is indestructible. You have to take care of your investment regardless of how much you paid.

The Do’s

First of all, do take care when you are cleaning your shades. Be as gentle as you possibly can so that you don’t risk scratching the lenses or breaking the hinges. A gentle approach starts with a bit of air to blow off any loose dirt and debris. You can blow with your mouth or use one of those cans of compressed air that computer technicians rely on to clean delicate electronic components.

Next, do make a point to use warm water and a mild detergent on grease, makeup, sunblock, and the like. The detergent acts as a surfactant that breaks the bond between the surface of the lens and whatever substance you are trying to remove. Once the bond is broken, the warm water will rinse the dirt away.

Finally, do dry your sunglasses with a clean, cotton cloth. Cotton is the best material for cleaning and drying sunglasses because it will not scratch the lenses. You obviously want a clean cloth so that you do not transfer dirt back onto the lenses as you are drying them.

The Don’ts

Now that we have covered the do’s, let us address the don’ts of cleaning sunglasses. The biggest don’t is putting your sunglasses into their case while still dirty. Doing so just transfers the dirt, meaning your sunglasses are likely to get dirty again every time you put them into, and take them out of, that case.

Also do not wipe the lenses down without first blowing off loose dirt and debris. Otherwise, any course debris could put a deep scratch in the lenses. Be patient and don’t skip the blowing off step.

As long as we are talking about wiping down the lenses, don’t ever use a paper product to do so. All paper products – napkins, tissues, etc. – are made from wood. Even the finest paper can still have tiny chips of wood embedded in it. Those tiny chips can easily scratch lenses.

Last but not least, never use solvents or harsh ammonia-based cleaners on sunglasses. Such substances can damage lenses to the point of making them useless for eye protection. Leave those harsh chemicals for the big cleanup jobs in the garage and the kitchen. Stick with mild dish or laundry detergent for cleaning your shades.

Remember, there are right and wrong ways to clean sunglasses. Do not risk your investment by being careless with your cleaning. Rather, take care of your sunglasses as best you can. They will take care of you in return, giving you years reliable service.