One of the most common questions people have when first unboxing their Glowforge is “what is this blue thing that looks like a loose part?” This is a lens removal tool to help get the main lens out of the head of the printer for cleaning. It has a magnetic ring at the top of the tool that you simply insert into the head. You will hear it “grab” the lens, then you can simply remove the tool and the lens will come with it.
To re-insert the lens, place the lens on the reverse side of the tool (without the magnet) and insert it back into the print head.
WARNING
When removing the lens, be sure to do it over a piece of cloth and not too far off your work surface so that it it does fall, it will not take any damage.
Keep spares
It is always a good idea to keep a spare set of lenses/mirrors/windows on-hand in case you need to replace them in the middle of that project THAT HAS TO BE DONE RIGHT NOW!