Why Your Clear Phone Case Turned Yellow (And Can It Be Cleaned?)

Every smartphone buyer faces a dilemma from the moment they unbox it. Your new phone is designed to look gorgeous, but although you can somewhat protect your phone without a bulky case, that means leaving it prone to damage from drops and scuffs. For many people, the solution is a clear case that leaves the phone's design and colors visible, but still offers a protective shell around it. 

As anyone who's owned a clear phone case for a long period of time can attest, they quickly turn a disgusting shade of yellow reminiscent of a grimy, public restroom. It's frankly gross, and it can happen rather quickly, even to phone cases from major brands. Given how expensive cases can be, it can also make you feel like you've wasted money.

If you've experienced case yellowing, you might wonder why it happens. Is it dirt buildup? Do non-clear cases reach a similar level of grossness that goes unnoticed because you can't see it as well? The answer to both questions is no. While the material most high quality clear cases are made from protects your phone from drops, it also turns naturally yellow when the chemical mixture its made from degrades. 

There are ways to mitigate the yellowing, but reversing it may not be possible. Here's how yellowing happens, how you can avoid it, and what you can do to keep your case clean.

Among the most common materials for phone cases are plastic in the form of polycarbonate or TPU (thermoplastic polyurethane). These more pliable plastics help to absorb and redistribute the energy that transfers to your phone when it hits the ground during a drop, but they are also prone to yellowing.

One of the most common causes of yellowing is UV light . UV rays from sunlight break your case down at the molecular level, and that chemical reaction is what you're seeing when the case goes yellow. This means the quickest way to ensure your case goes from crystal clear to sickly yellow is leaving it in the sun. 

Of course, you shouldn't leave it in the sun anyway if you want to stop your phone from overheating. Heat is another common cause of yellowing, including the heat that comes from your hands when you hold the phone for extended periods of time. Your hands can also yellow the case by leeching your body's natural oils and sweat into it, which also react chemically.

With clear cases so prone to yellowing when exposed to these incredibly common elements, it's expected for them to yellow over time. It's more a question of when, rather than if it will yellow. As a consumer, do research into a case before buying it: Higher quality materials are likely to yellow slower than low quality ones, and you can also examine user reviews to see how quickly people report yellowing. If you'd rather not contribute to plastic waste by tossing a yellowed case, consider another use for an old phone case.

At this point, you might be looking at your formerly clear but now banana yellow phone case, thinking, "I'll avoid leaving it in the sun next time, but what can I do to reverse this?" Unfortunately, once a case has turned yellow from the sun or other chemical reactions, there's not much you can do about it. Once the chemicals in your case materials have broken down, they can't be fully restored.

What you can do is clean your clear case, since a portion of the yellowing might be due to regular old dirt and grime, rather than chemical reactions. Using a microfiber cloth (or paper towel in a pinch) and a mixture of water and dish soap, vinegar, or baking soda, thoroughly wipe the case down inside and out, taking care to get in the little crevices. Rubbing alcohol or a natural electronics cleaning spray can also be helpful. Use a dry cloth or paper towel to dry it off with equal carefulness. If it's still yellow, you're out of luck.

If your clear case hasn't yet yellowed, avoid the main causes of yellowing, and clean the case regularly. Cleaning it will help to remove any sweat, oil, or other gunk that could cause yellowing over time. Ultimately, though, clear cases are very hard to prevent from yellowing over time. 

When you purchase one, you should factor that into your decision. If you don't want to replace your case regularly  — which contributes to plastic waste, in addition to its costliness  — you might want to opt for a colored case that will show signs of aging less readily.