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[.]

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[wbd]

I always still have to degrease bones that are beetle cleaned, so I would say they don't. Or at least not to that extend that you do not have to degrease anymore..

[jrm123]

My experience is that the beetles eat most of the stuff in the vein holes.  I still run a pipe cleaner down them but get very little grease or fat.

[The Dog]

I throw the fat I cut off of steaks in there, they eat it right up.  I would think if they can get to it physically they will eat it.