Fungus happens. It typically becomes an issue with older lenses regardless of brand, price tag, or fanciness, but there are several ways to counteract this unfortunate formation on your precious glass elements. Photographer and master of weird lenses Mathieu Stern has shared a quick video to show you how to clean up your fungus problems safely and simply with hot water, dish soap, and white vinegar. Check it out below:

After Stern disassembles his lens, he runs it under hot water, gently washes it with dish soap, pat dries with a paper towel, then pours white vinegar over it to get rid of any residue. If you don't have white vinegar (I assume everybody has dish soap), Tom Leonard did a write-up for PetaPixel that shows you how to clean up fungus with hydrogen peroxide, so that might be worth looking into as well.

Though many, including myself, consider Stern a professional when it comes to lenses, I personally have never cleaned a lens using the mixture of ingredients mentioned in the video, so proceed with caution if you decide to try this on your own lenses. There are many solutions that could damage the glass/coating on your lenses, so it's good to be aware before you start. Also, this requires you to take your lens apart, so if you don't know what you're doing, don't risk ruining your glass.

If disassembling your lens and cleaning it yourself isn't up your alley, you can always send your lenses off to a professional, though it'll cost a lot more than soap and vinegar.

Source: Mathieu Stern