In the 4+ years our team has been working to eliminate germs on smartphones, tablets and other devices, we’ve seen lots of terminology used regarding our own and other solutions.

For many people, the words ‘clean’ and ‘sanitize’ are synonymous. They assume that cleaning their phone will kill all the bugs, or that sanitizing a phone will clean it. But these words can mean very different things, especially in terms of infection control.

Cleaning ≠ Sanitizing

To clean a phone screen is simply to physically wipe it down. This can be done with a microfiber cloth, a wet wipe, or just the sleeve of your shirt; essentially any common soft tissue or fabric. Each of these items work because they successfully “clean” a touchscreen by physically removing visible debris (such as dirt, grease, oils and dust). They’re purpose is not to kill or reduce a certain number of bacteria.

So while a phone may look cleaner after being wiped down, the act of cleaning doesn’t address the microscopic superbugs which may be lurking on your cell phone or phone case.

Sanitizing A Surface

Sanitization can be achieved in several different ways, including germicidal ultraviolet (UV) light. In contrast to cleaning (which emphasizes the removal of debris, but doesn’t define any reduction in bacteria), the act of sanitization focuses almost exclusively on reducing bacterial counts on a given surface. To ‘sanitize’ a surface, you need to deactivate at least 99.9% of pathogens.

In many cases, the debris or “soiling” on a surface can actually impact the effectiveness of sanitization products. This debris can act as an umbrella, protecting bacteria from powerful UV rays that would otherwise kill them. This is why it’s very important for any type of sanitizer to either include soiling in their efficacy testing (which ASTM E1153 does) or to explicitly note that people need to clean a surface before using a certain sanitization technology.

If you’d like to learn more about soiling and the impact on efficacy claims, you can check out our Guide to Evaluating Countertop UV-C.