I think if you empty the shredder and shred new blank paper it would be safe, maybe even buy the special paper made of organic material if you are really worried, but a lot of shredders also shred staples and CDs. So bits of metal staples, CDs, ink and other dangerous contaminates could be in the shredded paper from your office, I wouldn't risk having bits of metal, CD and ink in there personally or recommend it to anyone, but like I said if you clean out the shredder paper bin and use brand new paper that should be safe, you could even shred newspaper if you wanted I'm sure (never tried it, but don't see why not), I used newspaper sheets with my Leopard Gecko for 17 years with no problems, just recently switched to Zoo Med Excavator Clay Burrowing Substrate, don't see how shredded news paper would be any different than a sheet of newspaper.