Inside a faulty shredder. A thorough cleaning out was required before the fault-finding commenced.

Some tips for owners and users of shredders from someone that's had to contend with a few jammed up and faulty ones:

1) read and heed the instructions before using(!), especially the bits about using any lubricating oil/fluid provided, and what can and must not be put through them;

2) avoid putting sticky things through them, especially: labels; post-its; and the self-seal parts of envelopes. All of these items will lead to the cutting blades becoming gummed-up and then seizing no matter how much (of the correct) lubrication is applied;

3) don't take them apart unless you know what you're doing(!). Were you to take one apart, don't attempt to operate it whilst it's apart... unless you're happy to lose fingers, like electric shocks, or any other of the hazards.

4) don't let kids near them!