The bacterial fermentation of skin oils on used sunglasses nose pads

That slimy, green crust on your sunglasses nose pads isn’t just "dirt." It’s a thriving, microscopic buffet.

Your skin constantly leaks sebum—basically face grease—which gets trapped against the warm plastic. Bacteria move in like squatters at an all-you-can-eat buffet, gorging on those lipids and dead skin cells.

As they digest your grease, they "fart" out volatile fatty acids. That’s the source of that sour, cheesy funk. You’re essentially wearing two tiny, fermented petri dishes right on the bridge of your nose.

But wait, why on earth is that crusty gunk specifically green?

It’s basically the Statue of Liberty effect, but way grosser. Most nose pads contain tiny metal components, like screws or wires made of copper or nickel. When those bacterial farts—the acidic fatty acids—hit the metal, they trigger a chemical reaction called oxidation.

That reaction creates copper salts like carbonates or chlorides, which are naturally a bright, swampy green. So, you’re not just wearing a bacterial buffet; you’re wearing a layer of corroded metal salts mixed with your own fermented face-juice.

So am I basically tattooing my nose with toxic metal sludge?

Not quite a tattoo, but you are essentially giving yourself a chemical hickey. Those copper salts are irritants. If you leave that swampy sludge there long enough, it starts to soak into the top layer of your dead skin cells.

It’s called contact dermatitis. Your immune system sees the oxidized metal as a hostile invader and freaks out, leading to red, itchy, or even peeling patches. You're not just wearing gunk; you're hosting a slow-motion chemical burn on your face.

The green can even temporarily dye your skin. You’ll take the glasses off and still look like you’re growing moss on your snout. It’s a lovely, itchy souvenir of your own neglected hygiene.

Can't I just scrub that green stain off with some soap and water?

Good luck. Your skin isn't a smooth surface; it’s a jagged stack of porous shingles. The copper salts don't just sit on top; they seep into the microscopic cracks between your dead skin cells.

Once wedged in, they’re part of your 'outer crust' until those cells naturally flake off. You’d practically have to sand your face to remove it instantly.

You just have to wait for your body’s conveyor belt to push those stained, dead cells out. Until then, you’re stuck as a human-metal hybrid.

Wait, how long does this skin conveyor belt take to dump the green?

Your skin is basically a slow-motion escalator of dying meat. It takes about a month—roughly 28 to 40 days—for a fresh cell born at the bottom to travel up, die, and finally flake off into the abyss of your bedsheets.

Since that green sludge is wedged into the "top floor" shingles, you’re stuck with it for at least a week or two. You’re literally waiting for your body to shed its own stained armor.

Until then, you're just a walking billboard for copper oxidation. Every time you touch your nose, you're just wiggling the dead, dyed scales that haven't realized they're already fired from the job.