When Fellowes claimed that its new deskside paper shredder was jam-proof, the editors at Popular Mechanics were rightly skeptical. Shredders jam. That's just what they do. What if you try to shred sheet metal? Wouldn't the machine jam then? Not really. Turns out that these shredders aren't super powerful, instead, what they have going for them is excellent damage control. If you put something in the shredder that it doesn't like— folded papers, for example— it will stop and let you pull them out before they get stuck. All shredders should do this. But since they don't, a Fellowes shredder may be a good bet: Popular Mechanics tests showed that the model is surprisingly jam-proof.
Now, if you want a shredder that jams you should get this paper shredder/MP3 player combo instead.