Clean crumb tray

Hi all!
I’m trying to find any info about cleaning the crumb tray. I’m getting more flashback than usual, and feel it may be due to excessive gunk and crap from lasering… in any event, I’d like to clean it anyhow. :slight_smile:
I seem to recall a post a long while back that I can’t find, about using simple green and soaking? Anyone tried anything better? Or have a solid workable method for doing It? Thanks in advance!!

  • R
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Yes…from long ago;


I used this method on my PRU and it was never 100% flat or level after I re-assembled it. Others have had great success, but I just want to mention the success rate is not 100%. YMMV. Best of luck.


Thank You! Yes, that’s the one… :slight_smile:

And this is exactly what I am wary of… Taking it apart may change the perfect level of the actual crumb tray honeycomb. :confused:

Has anyone else tried another method? Any recommendations from Glowforge? @dan

Mine, after many months,loads of projects cut, and various materials (plywood, hardwoods, acrylics, cardstock, leather, etc.), it is really dirty and gunked up… definitely causing flashback and more burn on the backside, and probably becoming more and more unsafe…

Any official recommendation or advice would be very helpful! <3

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I’ve done the Simple Green but haven’t disassembled the crumb tray. Maybe it doesn’t get as clean as disassembling it - but it still does a heck of a job. I just filled the guest tub with a little water and a little simple green :man_shrugging:t2:

Fair warning: it will hold a lot of water. I take it from the tub to outside into the Texas sun and keep a fan blowing across it. Usually overnight.


I just give it a good brushing periodically with a stiff wire brush. Knocks off most of the gunk. The rest is keeping it from rusting. (Because I brush it with a stiff wire brush.) :smile:


To be honest, I’m pretty surprised to hear gunk buildup is causing MORE flashback. It should be the opposite unless that gunk is made of reflective material. Maybe it’s the case that you have so much gunk that it’s catching on fire?, which is pretty dangerous.

Personally I have a tiny shop vac I keep close to my forge and I vacuum the pieces afterwards as well as whatever residue is in the machine. Vacuuming your pieces really helps with weeding, because it removes all the dust that gunks up your tape, causing it not to adhere to the masking as well.

I also cover my bed in tape which means everything that deposits anywhere is usually on the tape, then I just remove and replace it once every so often.


It might not technically be flashback but staining as the gunk reheats and gets sticky again.


Hmmm… it definitely happened quite a bit from the last few jobs a ran using mahogany, but could also be the power setting with the wood itself. Soft spots on the wood that are ‘charred holes’, usually where sharp points, corners, are in a design. Like, overburn… only happens on the back, bed side of the cut pieces. I figured it was flashback, but maybe not?
I do tests to get best settings with each wood type I use, but I may need to adjust more and dial in for this wood. :wink:
In any event, I do want to clean my honeycomb so I appreciate the advice and insight from all commenters here. Thanks!

  • R

Sounds like it’s overbaking your corners. I’d first check to make sure you don’t have to many points in your design where those spots are, and if not maybe let support know.

There’s definitely an issue with having too much power on the corners of cuts and scores, however I’ve never had an issue with flashback due to it.

In the meantime if you aren’t doing anything too thick, you could use a shim to keep it off the bed. A piece of wasteboard or pegs to heighten it. That will let you know whether you’re dealing with flashback or something else.


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