Lens Cleaning of SO-2 10W Laser


I’ve just purchased the 10 W SO-2 Laser Engraver.
I am happy with the device.

But after some time of working with it, I noticed that the laser power is decreasing. I need more time to cut 3mm wood plates than before.

I think the lens is dirty from smoke and dust. It is possible to clean the lens? How can I disassemble the nozzle to reach the lens for cleaning?

Thanks for helping.

Best regards,