Cleaning Stubborn Lenses

So my lenses have a… film? On them. It looks kinda like if you wipe something down with water and let it dry. I assume it’s because I use the unit so much. I’ve wiped everything down with lens paper, replaced the mirror because it had the dreaded black dot of doom (no shock, I’ve been using it a lot for a year and a half). I work entirely in hardwood and plywood.

My cuts are still taking a significant increase in power (or decrease in speed) to cut through reliably (though after the mirror change it’s still mostly within the range the laser can do, so yay improvement). So I want to clean the side lenses more thoroughly, and maybe try to get that film off. Is there a lens cleaning solution recommended for this?

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I use a 50/50 mixture of vinegar and water. Moisten a soft microfiber lens cloth with it, not a paper towel, and gently wipe. Film comes right off. Also great for wiping down the interior to get rid of the film.

Or you can use Zeiss wipes if you want to pay a ridiculous amount of money for them.


Perfect! Thank you! I’ll try that. It seems like the only thing left that could be affecting power. And vinegar is easy.

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The anti-reflective coating on the windows, mirror, and lens allow them to be easily cleaned with a simple wipe using a mild solvent. It’s also critical to beam transmission, so be VERY careful not to damage it.

Power reduction over time is expected from the tube. It was initially estimated they would have a two-year lifespan with moderate use.

So I may actually be nearing the end of it’s lifetime. Ugh.

Depends on use. Mine is lightly used, coming up on three years, but tubes have a shelf life regardless of use as well, so I wouldn’t be surprised if mine started to degrade.

I use mine pretty regularly. Moderate to heavy.

Good thing I saved that original packing.

I’m sorry you’ve hit a snag. As per the Glowforge manual, after every 40 hours of printing, use ZEISS lens cleaning wipes (available on Amazon and many other stores) to clean the cameras, laser lens, and windows. This will keep the unit working properly and prevent permanent damage to your unit.

Do you mind sending me some photos of the optics showing the film as this will help me better understand the issue you’re experiencing.

Sorry, I can’t. I used Jules’ suggestion of 50/50 vinegar and water already and the film came off.


I’m glad you resolved it! I’m going to close this thread. If you run into any other trouble, please start a new topic, or email us at We’re here to help!